CODEWITHSUNDEEP
carraysalgorithm
Evan
Evan

Reputation: 11

Crashing with no errors, sorting algorithm

The purpose of the program is to create a random list of 1000 numbers in an array, sort that array, then find the greatest set of numbers within (x, x+50). The program successfully generates and sorts the numbers within the array, but crashes when the (i, j) set finding algorithm starts. The program generates no errors on compiling, and I'm sure the error is simple, but for the life of me I can't find the issue. Thanks in advance you amazing people!

int main( ){

    int a, b, temp, i, j, x, y, tempTotal, arrayStartMax;
    int finalTotal = 0;
    int *info[ARRAY_FULL];

    for (i=0; i<ARRAY_FULL; i++){
        info[i]=(int*)malloc(sizeof(int));
        *info[i]=rand()%1000;
    }

    for (a = 0; a < ARRAY_FULL; ++a){
        for (b = a + 1; b < ARRAY_FULL; ++b){
            if (*info[a] > *info[b]){
                temp = *info[a];
                *info[a] = *info[b];
                *info[b] = temp;
            }
        }
    }

    for (i=0; i<ARRAY_FULL; i++){
        printf("%d\n", *info[i]);
    }

    for (i = 0; i <= ARRAY_HALF; i++){
        x = *info[i];
        y = x+ARRAY_HALF;
        tempTotal = 0;
        for (j = i; j < i+ARRAY_HALF; i++){
            if (*info[j] >= x || *info[j] <= y) {
                tempTotal++;
            }
            if (tempTotal > finalTotal) {
                arrayStartMax = *info[i];
                finalTotal = tempTotal;
            }
        }
    }

    printf("Interval should start at %d for maximum numbers in a set.", arrayStartMax);

}

For the purpose of this program I would like to mention that ARRAY_FULL = 100 and ARRAY_HALF = 50.

Upvotes: 0

Views: 67

Answers (1)

John
John

Reputation: 34

Your code is throwing segfault because you're walking i out of bounds in this for loop.

for (j = i; j < i+ARRAY_HALF; i++){
        if (*info[j] >= x || *info[j] <= y) {
            tempTotal++;
        }
        if (tempTotal > finalTotal) {
            arrayStartMax = *info[i];
            finalTotal = tempTotal;
        }

You set j = i then increment i prior to the comparison. So j will always be less than i.

Limit i in the comparison section of the for loop and it won't segfault.

I don't think the comparison is doing what you want, but you should be able to find your way home from here.

Upvotes: 1

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