Number of digits used in integer

#include <stdio.h>
#include <string.h>
int main(void){
char var[20];
int num;
printf("Enter a number ");
scanf("%d",&num);
sprintf(var,"%d", num);
printf(" number of digits = %d", strlen(var));
return 0;
}

Example: Recursive Function to Count Digits

#include <stdio.h>

int countDigits(int num) {
    if (num == 0)
        return 0;
    return 1 + countDigits(num / 10);
}

int main() {
    int number = 12345;
    printf("Number of digits: %d\n", countDigits(number));
    return 0;
}

Number of digits : 5 

Example: Counting Even and Odd Digits

#include <stdio.h>

int main() {
    int num = 123456, even = 0, odd = 0;

    while (num != 0) {
        int digit = num % 10;
        if (digit % 2 == 0)
            even++;
        else
            odd++;
        num /= 10;
    }

    printf("Even digits: %d, Odd digits: %d\n", even, odd);
    return 0;
}

Even digits: 3, Odd digits : 3