// C program to replace all ‘0’ with ‘5’ in an input Integer
#include<stdio.h>
 
// A recursive function to replace all 0s with 5s in an input number
// It doesn't work if input number itself is 0.
int convert0To5Rec(int num)
{
    // Base case for recursion termination
    if (num == 0)
        return 0;
 
    // Extraxt the last digit and change it if needed
    int digit = num % 10;
    if (digit == 0)
        digit = 5;
 
    // Convert remaining digits and append the last digit
    return convert0To5Rec(num/10) * 10 + digit;
}
 
// It handles 0 and calls convert0To5Rec() for other numbers
int convert0To5(int num)
{
    if (num == 0)
       return 5;
    else return  convert0To5Rec(num);
}
 
// Driver program to test above function
int main()
{
    int num = 10120;
    printf("%d", convert0To5(num));
    return 0;
}