CODEWITHSUNDEEP
carraysrandom
Cam9191
Cam9191

Reputation: 33

Scramble numbers from array with numbers - C

I have been figuring out how to scramble numbers from array after user enters 10 different numbers by using rand(). It crushes when it arrives to adjust() function so feel free to point out my stupid mistake. Cheers. The top part is function, the bottom part is in main().

void adjust(int z[], int size)
{
    int i, n, t;

    for(i = 0; i < size; i++)
    {
        size = rand();
        t = z[size];
        z[size] = z[i];
        z[i] = t;
    }

    printf("\nYour numbers have been scrambled and here they are: \n", t);
}

.....................

int z[10];
int i;
int num = 0;

printf("Please enter 10 different numbers: \n");

for(i = 0; i < 10; i++)
{
    z[i] = num;
    scanf("%d", &num);
}

printf("\nThe numbers you entered were: ");

for (i = num; i <= 10; i++)
{
    printf("%d ", z[i]);
}
printf("\n");

addNum(z, 10);

adjust(z, 10);

return 0;

Upvotes: 0

Views: 786

Answers (1)

shr
shr

Reputation: 1025

The rand() function returns a number between 0 and RAND_MAX. Hence, the array index can go well beyond its range.

To get a random index within a range from 0 to N -1 , use rand() % N.

Another issue is that in your for loop, in adjust function, you are destroying the original value of 'size'. That contains the length of your array and is used to check the terminating condition of your for loop. Hence, do not modify 'size'. Use another variable to store your random index. 

for(i = 0; i < size; i++)
{
    n = rand() % size;   // n is between 0 and size-1
    t = z[n];
    z[n] = z[i];
    z[i] = t;
}

// For a better design move the following lines to a separate function
// that way adjust function just does the scrambling while another
// printing function prints out the array. Each function does only one thing.
printf("\nYour numbers have been scrambled and here they are: \n");
for( i = 0; i < size; i++)
{
   printf("%d ", z[i]);
}

Upvotes: 3

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