Question

How to write a recursive function that counts digits of a number in C

Answer 1

#include <stdio.h>
#include <stdlib.h>

int countDigits(long num) {
    // Base case: If the number is reduced to 0, return 0
    if (num == 0) {
        return 0;
    }
    // Recursive case: Divide the number by 10 and add 1
    return 1 + countDigits(num / 10);
}

int main() {
    long number = 19938420;

    // Handle the case for 0 explicitly
    if (number == 0) {
        printf("The number of digits is: 1\n");
    } else {
        // Use the recursive function with the absolute value of the number
        printf("The number of digits is: %d\n", countDigits(abs(number)));
    }

    return 0;
}



/*
run:

The number of digits is: 8

*/

 

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