Project Euler # 11, variables overflowing

Question

Trying to solve project euler #11 and I keep getting a negative number for the two biggest products I'm outputting. Sort of at my wits end, and I figured by using long long data type I'd be safe, but I have no idea what is going on. I don't know what else to try, I'm probably doing something very silly but I've been spinning my wheels in the sand for a few hours and it's time to reach out I think

#include <iostream>
#include <fstream>
#include <iomanip>
using namespace std;

long long hZ (int matrix[20][20], int i, int j);

int main()
{
    fstream inFile;
    int matrix [20][20];
    long long max = 0;
    inFile.open("numbers.txt");
    if(!inFile)
        cout << "numbers.txt failed to open!" << endl;

    for(int i = 0; i < 20; i++)
        for(int j = 0; j < 20; j++)
            inFile >> matrix[i][j];

    for(int i = 0; i < 20; i++)
    {
        for(int j = 0; j < 16; j++)
        {
            long long temp = hZ(matrix, i, j);
            if (temp > max)
                max = temp;
            cout << matrix[i][j] << " " << matrix[i][j+1] << " " << matrix[i][j+2] << " " << matrix[i][j+3] << " " << matrix[i][j+4];
            //cout.setf(ios::fixed);
            cout << " product: " << temp << " max: " << max << endl;
        }
        cout << endl;
    }
    cout << "The max is: " << max;
    return 0;
}

long long hZ (int matrix[20][20], int i , int j)
{
        long long hZ_product = 0;
        hZ_product = (matrix[i][j] * matrix[i][j+1] * matrix[i][j+2] * matrix[i][j+3] * matrix[i][j+4]);

    return hZ_product;
}

OUTPUT: (if you scroll down on the output to nearly the end you will see where I commented on the lines that are causing issues):

8 2 22 97 38 product: 1297472 max: 1297472
2 22 97 38 15 product: 2432760 max: 2432760
22 97 38 15 0 product: 0 max: 2432760
97 38 15 0 40 product: 0 max: 2432760
38 15 0 40 0 product: 0 max: 2432760
15 0 40 0 75 product: 0 max: 2432760
0 40 0 75 4 product: 0 max: 2432760
40 0 75 4 5 product: 0 max: 2432760
0 75 4 5 7 product: 0 max: 2432760
75 4 5 7 78 product: 819000 max: 2432760
4 5 7 78 52 product: 567840 max: 2432760
5 7 78 52 12 product: 1703520 max: 2432760
7 78 52 12 50 product: 17035200 max: 17035200
78 52 12 50 77 product: 187387200 max: 187387200
52 12 50 77 91 product: 218618400 max: 218618400
12 50 77 91 8 product: 33633600 max: 218618400

49 49 99 40 17 product: 161635320 max: 218618400
49 99 40 17 81 product: 267193080 max: 267193080
99 40 17 81 18 product: 98152560 max: 267193080
40 17 81 18 57 product: 56512080 max: 267193080
17 81 18 57 60 product: 84768120 max: 267193080
81 18 57 60 87 product: 433813320 max: 433813320
18 57 60 87 17 product: 91047240 max: 433813320
57 60 87 17 40 product: 202327200 max: 433813320
60 87 17 40 98 product: 347860800 max: 433813320
87 17 40 98 43 product: 249300240 max: 433813320
17 40 98 43 69 product: 197720880 max: 433813320
40 98 43 69 48 product: 558270720 max: 558270720
98 43 69 48 4 product: 55827072 max: 558270720
43 69 48 4 56 product: 31901184 max: 558270720
69 48 4 56 62 product: 45997056 max: 558270720
48 4 56 62 0 product: 0 max: 558270720

81 49 31 73 55 product: 494001585 max: 558270720
49 31 73 55 79 product: 481804015 max: 558270720
31 73 55 79 14 product: 137658290 max: 558270720
73 55 79 14 29 product: 128777110 max: 558270720
55 79 14 29 93 product: 164058510 max: 558270720
79 14 29 93 71 product: 211784622 max: 558270720
14 29 93 71 40 product: 107232720 max: 558270720
29 93 71 40 67 product: 513185160 max: 558270720
93 71 40 67 53 product: 937890120 max: 937890120
71 40 67 53 88 product: 887465920 max: 937890120
40 67 53 88 30 product: 374985600 max: 937890120
67 53 88 30 3 product: 28123920 max: 937890120
53 88 30 3 49 product: 20568240 max: 937890120
88 30 3 49 13 product: 5045040 max: 937890120
30 3 49 13 36 product: 2063880 max: 937890120
3 49 13 36 65 product: 4471740 max: 937890120

52 70 95 23 4 product: 31813600 max: 937890120
70 95 23 4 60 product: 36708000 max: 937890120
95 23 4 60 11 product: 5768400 max: 937890120
23 4 60 11 42 product: 2550240 max: 937890120
4 60 11 42 69 product: 7650720 max: 937890120
60 11 42 69 24 product: 45904320 max: 937890120
11 42 69 24 68 product: 52024896 max: 937890120
42 69 24 68 56 product: 264854016 max: 937890120
69 24 68 56 1 product: 6306048 max: 937890120
24 68 56 1 32 product: 2924544 max: 937890120
68 56 1 32 56 product: 6823936 max: 937890120
56 1 32 56 71 product: 7124992 max: 937890120
1 32 56 71 37 product: 4707584 max: 937890120
32 56 71 37 2 product: 9415168 max: 937890120
56 71 37 2 36 product: 10592064 max: 937890120
71 37 2 36 91 product: 17212104 max: 937890120

22 31 16 71 51 product: 39512352 max: 937890120
31 16 71 51 67 product: 120333072 max: 937890120
16 71 51 67 63 product: 244547856 max: 937890120
71 51 67 63 89 product: 1360297449 max: 1360297449
51 67 63 89 41 product: 785523879 max: 1360297449
67 63 89 41 92 product: 1417023468 max: 1417023468
63 89 41 92 36 product: 761385744 max: 1417023468
89 41 92 36 54 product: 652616352 max: 1417023468
41 92 36 54 22 product: 161320896 max: 1417023468
92 36 54 22 40 product: 157386240 max: 1417023468
36 54 22 40 40 product: 68428800 max: 1417023468
54 22 40 40 28 product: 53222400 max: 1417023468
22 40 40 28 66 product: 65049600 max: 1417023468
40 40 28 66 33 product: 97574400 max: 1417023468
40 28 66 33 13 product: 31711680 max: 1417023468
28 66 33 13 80 product: 63423360 max: 1417023468

24 47 32 60 99 product: 214410240 max: 1417023468
47 32 60 99 3 product: 26801280 max: 1417023468
32 60 99 3 45 product: 25660800 max: 1417023468
60 99 3 45 2 product: 1603800 max: 1417023468
99 3 45 2 44 product: 1176120 max: 1417023468
3 45 2 44 75 product: 891000 max: 1417023468
45 2 44 75 33 product: 9801000 max: 1417023468
2 44 75 33 53 product: 11543400 max: 1417023468
44 75 33 53 78 product: 450192600 max: 1417023468
75 33 53 78 36 product: 368339400 max: 1417023468
33 53 78 36 84 product: 412540128 max: 1417023468
53 78 36 84 20 product: 250024320 max: 1417023468
78 36 84 20 35 product: 165110400 max: 1417023468
36 84 20 35 17 product: 35985600 max: 1417023468
84 20 35 17 12 product: 11995200 max: 1417023468
20 35 17 12 50 product: 7140000 max: 1417023468

32 98 81 28 64 product: 455196672 max: 1417023468
98 81 28 64 23 product: 327172608 max: 1417023468
81 28 64 23 67 product: 223679232 max: 1417023468
28 64 23 67 10 product: 27614720 max: 1417023468
64 23 67 10 26 product: 25642240 max: 1417023468
23 67 10 26 38 product: 15225080 max: 1417023468
67 10 26 38 40 product: 26478400 max: 1417023468
10 26 38 40 67 product: 26478400 max: 1417023468
26 38 40 67 59 product: 156222560 max: 1417023468
38 40 67 59 54 product: 324462240 max: 1417023468
40 67 59 54 70 product: 597693600 max: 1417023468
67 59 54 70 66 product: 986194440 max: 1417023468
59 54 70 66 18 product: 264947760 max: 1417023468
54 70 66 18 38 product: 170644320 max: 1417023468
70 66 18 38 64 product: 202245120 max: 1417023468
66 18 38 64 70 product: 202245120 max: 1417023468

67 26 20 68 2 product: 4738240 max: 1417023468
26 20 68 2 62 product: 4384640 max: 1417023468
20 68 2 62 12 product: 2023680 max: 1417023468
68 2 62 12 20 product: 2023680 max: 1417023468
2 62 12 20 95 product: 2827200 max: 1417023468
62 12 20 95 63 product: 89056800 max: 1417023468
12 20 95 63 94 product: 135021600 max: 1417023468
20 95 63 94 39 product: 438820200 max: 1417023468
95 63 94 39 63 product: 1382283630 max: 1417023468
63 94 39 63 8 product: 116402832 max: 1417023468
94 39 63 8 40 product: 73906560 max: 1417023468
39 63 8 40 91 product: 71547840 max: 1417023468
63 8 40 91 66 product: 121080960 max: 1417023468
8 40 91 66 49 product: 94174080 max: 1417023468
40 91 66 49 94 product: 1106545440 max: 1417023468
91 66 49 94 21 product: 580936356 max: 1417023468

24 55 58 5 66 product: 25264800 max: 1417023468
55 58 5 66 73 product: 76847100 max: 1417023468
58 5 66 73 99 product: 138324780 max: 1417023468
5 66 73 99 26 product: 62007660 max: 1417023468
66 73 99 26 97 product: 1202948604 max: 1417023468
73 99 26 97 17 product: 309850398 max: 1417023468
99 26 97 17 78 product: 331073028 max: 1417023468
26 97 17 78 78 product: 260845416 max: 1417023468
97 17 78 78 96 product: 963121536 max: 1417023468
17 78 78 96 83 product: 824114304 max: 1417023468
78 78 96 83 14 product: 678682368 max: 1417023468
78 96 83 14 88 product: 765692928 max: 1417023468
96 83 14 88 34 product: 333763584 max: 1417023468
83 14 88 34 89 product: 309426656 max: 1417023468
14 88 34 89 63 product: 234866016 max: 1417023468
88 34 89 63 72 product: 1207882368 max: 1417023468

21 36 23 9 75 product: 11736900 max: 1417023468
36 23 9 75 0 product: 0 max: 1417023468
23 9 75 0 76 product: 0 max: 1417023468
9 75 0 76 44 product: 0 max: 1417023468
75 0 76 44 20 product: 0 max: 1417023468
0 76 44 20 45 product: 0 max: 1417023468
76 44 20 45 35 product: 105336000 max: 1417023468
44 20 45 35 14 product: 19404000 max: 1417023468
20 45 35 14 0 product: 0 max: 1417023468
45 35 14 0 61 product: 0 max: 1417023468
35 14 0 61 33 product: 0 max: 1417023468
14 0 61 33 97 product: 0 max: 1417023468
0 61 33 97 34 product: 0 max: 1417023468
61 33 97 34 31 product: 205805094 max: 1417023468
33 97 34 31 33 product: 111337182 max: 1417023468
97 34 31 33 95 product: 320516130 max: 1417023468

78 17 53 28 22 product: 43291248 max: 1417023468
17 53 28 22 75 product: 41626200 max: 1417023468
53 28 22 75 31 product: 75906600 max: 1417023468
28 22 75 31 67 product: 95957400 max: 1417023468
22 75 31 67 15 product: 51405750 max: 1417023468
75 31 67 15 94 product: 219642750 max: 1417023468
31 67 15 94 3 product: 8785710 max: 1417023468
67 15 94 3 80 product: 22672800 max: 1417023468
15 94 3 80 4 product: 1353600 max: 1417023468
94 3 80 4 62 product: 5594880 max: 1417023468
3 80 4 62 16 product: 952320 max: 1417023468
80 4 62 16 14 product: 4444160 max: 1417023468
4 62 16 14 9 product: 499968 max: 1417023468
62 16 14 9 53 product: 6624576 max: 1417023468
16 14 9 53 56 product: 5983488 max: 1417023468
14 9 53 56 92 product: 34405056 max: 1417023468

16 39 5 42 96 product: 12579840 max: 1417023468
39 5 42 96 35 product: 27518400 max: 1417023468
5 42 96 35 31 product: 21873600 max: 1417023468
42 96 35 31 47 product: 205611840 max: 1417023468
96 35 31 47 55 product: 269253600 max: 1417023468
35 31 47 55 58 product: 162674050 max: 1417023468
31 47 55 58 88 product: 409009040 max: 1417023468
47 55 58 88 24 product: 316652160 max: 1417023468
55 58 88 24 0 product: 0 max: 1417023468
58 88 24 0 17 product: 0 max: 1417023468
88 24 0 17 54 product: 0 max: 1417023468
24 0 17 54 24 product: 0 max: 1417023468
0 17 54 24 36 product: 0 max: 1417023468
17 54 24 36 29 product: 23001408 max: 1417023468
54 24 36 29 85 product: 115007040 max: 1417023468
24 36 29 85 57 product: 121396320 max: 1417023468

86 56 0 48 35 product: 0 max: 1417023468
56 0 48 35 71 product: 0 max: 1417023468
0 48 35 71 89 product: 0 max: 1417023468
48 35 71 89 7 product: 74311440 max: 1417023468
35 71 89 7 5 product: 7740775 max: 1417023468
71 89 7 5 44 product: 9731260 max: 1417023468
89 7 5 44 44 product: 6030640 max: 1417023468
7 5 44 44 37 product: 2507120 max: 1417023468
5 44 44 37 44 product: 15759040 max: 1417023468
44 44 37 44 60 product: 189108480 max: 1417023468
44 37 44 60 21 product: 90256320 max: 1417023468
37 44 60 21 58 product: 118974240 max: 1417023468
44 60 21 58 51 product: 163991520 max: 1417023468
60 21 58 51 54 product: 201262320 max: 1417023468
21 58 51 54 17 product: 57024324 max: 1417023468
58 51 54 17 58 product: 157495752 max: 1417023468

19 80 81 68 5 product: 41860800 max: 1417023468
80 81 68 5 94 product: 207100800 max: 1417023468
81 68 5 94 47 product: 121671720 max: 1417023468
68 5 94 47 69 product: 103646280 max: 1417023468
5 94 47 69 28 product: 42677880 max: 1417023468
94 47 69 28 73 product: 623097048 max: 1417023468
47 69 28 73 92 product: 609839664 max: 1417023468
69 28 73 92 13 product: 168679056 max: 1417023468
28 73 92 13 86 product: 210237664 max: 1417023468
73 92 13 86 52 product: 390441376 max: 1417023468
92 13 86 52 17 product: 90924704 max: 1417023468
13 86 52 17 77 product: 76100024 max: 1417023468
86 52 17 77 4 product: 23415392 max: 1417023468
52 17 77 4 89 product: 24232208 max: 1417023468
17 77 4 89 55 product: 25630220 max: 1417023468
77 4 89 55 40 product: 60306400 max: 1417023468

4 52 8 83 97 product: 13396864 max: 1417023468
52 8 83 97 35 product: 117222560 max: 1417023468
8 83 97 35 99 product: 223173720 max: 1417023468
83 97 35 99 16 product: 446347440 max: 1417023468
97 35 99 16 7 product: 37643760 max: 1417023468
35 99 16 7 97 product: 37643760 max: 1417023468
99 16 7 97 57 product: 61305552 max: 1417023468
16 7 97 57 32 product: 19815936 max: 1417023468
7 97 57 32 16 product: 19815936 max: 1417023468
97 57 32 16 26 product: 73602048 max: 1417023468
57 32 16 26 26 product: 19728384 max: 1417023468
32 16 26 26 79 product: 27342848 max: 1417023468
16 26 26 79 33 product: 28197312 max: 1417023468
26 26 79 33 27 product: 47582964 max: 1417023468
26 79 33 27 98 product: 179351172 max: 1417023468
79 33 27 98 66 product: 455276052 max: 1417023468

88 36 68 87 57 product: 1068287616 max: 1417023468
36 68 87 57 62 product: 752657184 max: 1417023468
68 87 57 62 20 product: 418142880 max: 1417023468
87 57 62 20 72 product: 442739520 max: 1417023468
57 62 20 72 3 product: 15266880 max: 1417023468
62 20 72 3 46 product: 12320640 max: 1417023468
20 72 3 46 33 product: 6557760 max: 1417023468
72 3 46 33 67 product: 21968496 max: 1417023468
3 46 33 67 46 product: 14035428 max: 1417023468
46 33 67 46 55 product: 257316180 max: 1417023468
33 67 46 55 12 product: 67125960 max: 1417023468
67 46 55 12 32 product: 65091840 max: 1417023468
46 55 12 32 63 product: 61205760 max: 1417023468
55 12 32 63 93 product: 123742080 max: 1417023468
12 32 63 93 53 product: 119242368 max: 1417023468
32 63 93 53 69 product: 685643616 max: 1417023468

4 42 16 73 38 product: 7456512 max: 1417023468
42 16 73 38 25 product: 46603200 max: 1417023468
16 73 38 25 39 product: 43274400 max: 1417023468
73 38 25 39 11 product: 29751150 max: 1417023468
38 25 39 11 24 product: 9781200 max: 1417023468
25 39 11 24 94 product: 24195600 max: 1417023468
39 11 24 94 72 product: 69683328 max: 1417023468
11 24 94 72 18 product: 32161536 max: 1417023468
24 94 72 18 8 product: 23390208 max: 1417023468
94 72 18 8 46 product: 44831232 max: 1417023468
72 18 8 46 29 product: 13830912 max: 1417023468
18 8 46 29 32 product: 6147072 max: 1417023468
8 46 29 32 40 product: 13660160 max: 1417023468
46 29 32 40 62 product: 105866240 max: 1417023468
29 32 40 62 76 product: 174909440 max: 1417023468
32 40 62 76 36 product: 217128960 max: 1417023468

20 69 36 41 72 product: 146655360 max: 1417023468
69 36 41 72 30 product: 219983040 max: 1417023468
36 41 72 30 23 product: 73327680 max: 1417023468
41 72 30 23 88 product: 179245440 max: 1417023468
72 30 23 88 34 product: 148642560 max: 1417023468
30 23 88 34 62 product: 127997760 max: 1417023468
23 88 34 62 99 product: 422392608 max: 1417023468
88 34 62 99 69 product: 1267177824 max: 1417023468
34 62 99 69 82 product: 1180779336 max: 1417023468
62 99 69 82 67 product: -1968137428 max: 1417023468   //ISSUE HERE
99 69 82 67 59 product: -2080725970 max: 1417023468   //ISSUE HERE
69 82 67 59 85 product: 1901116290 max: 1901116290
82 67 59 85 74 product: 2038878340 max: 2038878340
67 59 85 74 4 product: 99457480 max: 2038878340
59 85 74 4 36 product: 53439840 max: 2038878340
85 74 4 36 16 product: 14492160 max: 2038878340

20 73 35 29 78 product: 115588200 max: 2038878340
73 35 29 78 31 product: 179161710 max: 2038878340
35 29 78 31 90 product: 220884300 max: 2038878340
29 78 31 90 1 product: 6310980 max: 2038878340
78 31 90 1 74 product: 16103880 max: 2038878340
31 90 1 74 31 product: 6400260 max: 2038878340
90 1 74 31 49 product: 10116540 max: 2038878340
1 74 31 49 71 product: 7980826 max: 2038878340
74 31 49 71 48 product: 383079648 max: 2038878340
31 49 71 48 86 product: 445200672 max: 2038878340
49 71 48 86 81 product: 1163266272 max: 2038878340
71 48 86 81 16 product: 379842048 max: 2038878340
48 86 81 16 23 product: 123047424 max: 2038878340
86 81 16 23 57 product: 146118816 max: 2038878340
81 16 23 57 5 product: 8495280 max: 2038878340
16 23 57 5 54 product: 5663520 max: 2038878340

1 70 54 71 83 product: 22275540 max: 2038878340
70 54 71 83 51 product: 1136052540 max: 2038878340
54 71 83 51 54 product: 876383388 max: 2038878340
71 83 51 54 69 product: 1119823218 max: 2038878340
83 51 54 69 16 product: 252354528 max: 2038878340
51 54 69 16 92 product: 279718272 max: 2038878340
54 69 16 92 33 product: 180994176 max: 2038878340
69 16 92 33 48 product: 160883712 max: 2038878340
16 92 33 48 61 product: 142230528 max: 2038878340
92 33 48 61 43 product: 382244544 max: 2038878340
33 48 61 43 52 product: 216051264 max: 2038878340
48 61 43 52 1 product: 6547008 max: 2038878340
61 43 52 1 89 product: 12139244 max: 2038878340
43 52 1 89 19 product: 3781076 max: 2038878340
52 1 89 19 67 product: 5891444 max: 2038878340
1 89 19 67 48 product: 5438256 max: 2038878340

The max is: 2038878340

Answer 1

Thank you @ everyone for your help.

Here is the final code I came up with which worked. I'm sure it's possible to make it a bit more efficient like not running 4 separate for-loops to check horizontal, vertical, diagonal left, and diagonal right products but I couldn't figure out how to internally customize each for iteration parameters to achieve this. Additionally, as I wrote the code I realized that writing four functions really wasn't necessary because I ended up having 4 different for loops, and in the end writing functions didn't make the code any more simple and seeing how this is a Project Euler problem, maintainability isn't really a consideration. I'm obviously not a very experienced programmer so I feel like I make mistakes at every turn. Are there any glaring inefficiencies in my final product?

#include <iostream>
#include <fstream>
using namespace std;

int hZ (int matrix[20][20], int i, int j);
int vZ (int matrix[20][20], int i, int j);
int dZ_right (int matrix[20][20], int i, int j);
int dZ_left (int matrix[20][20], int i, int j);

int main()
{
    fstream inFile;
    int matrix [20][20];
    int hZ_max, vZ_max, dZ_right_max, dZ_left_max = 0;
    inFile.open("numbers.txt");
    if(!inFile)
        cout << "numbers.txt failed to open!" << endl;

    //Populates the array with data

    for(int i = 0; i < 20; i++)
        for(int j = 0; j < 20; j++)
            inFile >> matrix[i][j];

    //Horizontal Analysis

    for(int i = 0; i < 20; i++)
    {
        for(int j = 0; j < 17; j++)
        {
            int hZ_temp = hZ(matrix, i, j);
            if (hZ_temp > hZ_max)
            {
                hZ_max = hZ_temp;
                cout << "hZ: " << matrix[i][j] << " " << matrix[i][j+1] << " " << matrix[i][j+2] << " " << matrix [i][j+3] << endl;
            }
        }
    }

    //Vertical Analysis

    for(int i = 0; i < 17; i++)
        {
            for(int j = 0; j < 20; j++)
            {
                int vZ_temp = vZ(matrix, i, j);
                if (vZ_temp > vZ_max)
                {
                    vZ_max = vZ_temp;
                    cout << "vZ: " << matrix[i][j] << " " << matrix[i+1][j] << " " << matrix[i+2][j] << " " << matrix [i+3][j] << endl;
                }
            }
        }

    //Right Diagonal Analysis

    for(int i = 0; i < 17; i++)
    {
        for(int j = 0; j < 17; j++)
        {
            int dZ_right_temp = dZ_right(matrix, i, j);
                if (dZ_right_temp > dZ_right_max)
                {
                    dZ_right_max = dZ_right_temp;
                    cout << "dZ_right: " << matrix[i][j] << " " << matrix[i+1][j+1] << " " << matrix[i+2][j+2] << " " << matrix [i+3][j+3] << endl;
                }
        }
    }

    //Left Diagonal Analysis

    for(int i = 0; i < 17; i++)
    {
        for(int j = 3; j < 17; j++ )
        {
            int dZ_left_temp = dZ_left(matrix, i, j);
                if(dZ_left_temp > dZ_left_max)
                {
                    dZ_left_max = dZ_left_temp;
                    cout << "dZ_left: "<< matrix[i][j] << " " << matrix[i+1][j-1] << " " << matrix[i+2][j-2] << " " << matrix [i+3][j-3] << endl;
                }
        }
    }

    cout << "The max horizontal product is: " << hZ_max << endl;
    cout << "The max vertical product is: " << vZ_max << endl;
    cout << "The max right diagonal product is: " << dZ_right_max << endl;
    cout << "The max left diagonal product is: " << dZ_left_max << endl;

    return 0;
}

//Horizontal Analysis function

int hZ (int matrix[20][20], int i , int j)
{
        int hZ_product = 0;
        hZ_product = matrix[i][j] * matrix[i][j+1] * matrix[i][j+2] * matrix[i][j+3];

    return hZ_product;
}

//Vertical Analysis function

int vZ (int matrix[20][20], int i , int j)
{
        int vZ_product = 0;
        vZ_product = matrix[i][j] * matrix[i+1][j] * matrix[i+2][j] * matrix[i+3][j];

    return vZ_product;
}

//Right Diagonal function

int dZ_right (int matrix[20][20], int i , int j)
{
        int dZ_right_product = 0;
        dZ_right_product = matrix[i][j] * matrix[i+1][j+1] * matrix[i+2][j+2] * matrix[i+3][j+3];

    return dZ_right_product;
}

//Left Diagonal function

int dZ_left (int matrix[20][20], int i, int j)
{
    int dZ_left_product = 0;
    dZ_left_product = matrix[i][j] * matrix[i+1][j-1] * matrix[i+2][j-2] * matrix [i+3][j-3];

    return dZ_left_product;
}

Answer 2

A correct solution to this problem doesn't overflow an int. Read the problem description more closely, it wants "the greatest product of four adjacent numbers". The contents of the grid are two-digit numbers so the maximum possible value is 99^4 or 96059601. This fits comfortably in a 32-bit int. You shouldn't be multiplying five grid cells together when the problem only asks for four adjacent numbers. Once you've fixed that you still need to check all directions (horizontal, vertical, and diagonal). Keep working on it and good luck.

Answer 3

You are overflowing the 4-byte integer.

First of all, I would like to say that project euler wants you to multiply 4 integers. You multiplied 5 integers. If you only multipled 4 integers, you would not overflow.

Assuming you want to multiply 5 integers, this line doesn't cast to long long until the product is calculated.

hZ_product = (matrix[i][j] * matrix[i][j+1] * matrix[i][j+2] * matrix[i][j+3] * matrix[i][j+4]);

By which time it is too late, it has already overflowed.

The easiest way to fix this is:

hZ_product = (long long)matrix[i][j] * matrix[i][j+1] * matrix[i][j+2] * matrix[i][j+3] * matrix[i][j+4];

This casts the first integer to long long. The rest will cast/promote automatically.

Answer 4

The problem is that your product calculation is done at int precision and then stored into long long. You need to do the calculation at long long precision.

long long hZ_product = 1;
hZ_product *= matrix[i][j];
hZ_product *= matrix[i][j+1];
hZ_product *= matrix[i][j+2];
hZ_product *= matrix[i][j+3];
hZ_product *= matrix[i][j+4];

Answer 5

In this line:

hZ_product = (matrix[i][j] * matrix[i][j+1] * matrix[i][j+2] * matrix[i][j+3] * matrix[i][j+4]);

you are multiplying a bunch of integer values together and then assigning the result to a long long hZ_product. That is causing integer overflow.

Try casting each operand in the multiplication to long long to avoid the overflow.