Replace all 0's with 5's in a given number using sprintf and sscanf

Question

I am trying to replace all the 0's present in a given integer with 5's.

To do that i am using sprintf to convert integer to string and do the operations on the string and finally convert back the string into an integer

Below is the code:

#include<stdio.h>

int main() {

    int num=0, i=0;
    char str[10];

    printf("Enter the number: ");
    scanf("%d",&num);

    sprintf(str,"%d",num);
    printf("string str:%s",str);
    while(str[i]!='\0')
    {
        if(str[i]==0)
            str[i]=5;
        i++;
    }

    sscanf(str,"%d",&num);

    printf("\nBefore replacement: %s", str);
    printf("\nAfter replacement: %d", num);

}

I am getting wrong output

Could someone identify and correct what is wrong here. Thanks :)

Answer 1

scanf("%d", num); should be scanf("%d", &num);.

Also, this here

if (str[i] == 0)
    str[i] = 5;

should be

if (str[i] == '0')
    str[i] = '5';

Because 0 is just the same as '\0', but you want to replace the character representing 0.

Also, in your output, you got before and after mixed up.