Question

#include<stdio.h>

int max = 100;

int main()
{
    int a,j;

    int * arr = (int*)malloc(sizeof(int)*max);
    arr[max-1] = 1;
    scanf("%d",&a); 
    factor( arr, a);
    display(arr);
}

int factor( int arr[],int a)
{
    if (!a) return;
    int i,carry;
    for(i=max-1;i>=0;i--)
    {
        arr[i] = (arr[i]*a) + carry;
        carry = arr[i]/10;
        arr[i] = arr[i]%10;

    }
    factor( arr, a-1);
}   

int display(int arr[])
{
    int i;
    for ( i=0; i<max; i++)
    {
        printf("%d",arr[i]);
    }
}

HI this is my program to find the factorial of numbers but its giving wrong answer i dont know why …???

like when i give input as 13
then according to myprogram 13 is to be treated in array as 1 and 3 but its giving random numbers -1216731443 -121673144 . i think malloc is having problem , but i can’t identify it .

thank you

Answer 1

I think the reason why you are getting “random” numbers is because you haven’t initialized the carry variable. In the for loop, you are adding the un-initialized value of carry to the array which will cause undefined results.