C++ Exercises: Find the number of trailing zeroes in a given factorial

Last update on December 20 2024 12:24:16 (UTC/GMT +8 hours)

Write a C++ program to find the number of trailing zeroes in a given factorial.

Input: n = 4
Output: 0
Input: n = 6
Output: 1

Sample Solution:

C++ Code :

#include <iostream>
using namespace std;

// Function to count the number of trailing zeroes in the factorial of a number
int trailing_Zeroes(int n) {
    int number = 0; // Initialize the count of trailing zeroes to 0
    while (n > 0) {
        number += n / 5; // Count the number of multiples of 5 in n
        n /= 5; // Reduce n to the next lower number for further count of trailing zeroes
    }
    return number; // Return the total count of trailing zeroes in the factorial of the given number
}

int main(void) {
    // Test cases to find the number of trailing zeroes in factorials of different numbers
    int n = 4;
    cout << "\nNumber of trailing zeroes of factorial " << n << " = " << trailing_Zeroes(n) << endl;

    n = 6;
    cout << "\nNumber of trailing zeroes of factorial " << n << " = " << trailing_Zeroes(n) << endl;

    n = 7;
    cout << "\nNumber of trailing zeroes of factorial " << n << " = " << trailing_Zeroes(n) << endl;

    n = 10;
    cout << "\nNumber of trailing zeroes of factorial " << n << " = " << trailing_Zeroes(n) << endl;

    return 0; // Return 0 to indicate successful completion
}

Sample Output:

Number of trailing zeroes of factorial 4 = 0

Number of trailing zeroes of factorial 6 = 1

Number of trailing zeroes of factorial 7 = 1

Number of trailing zeroes of factorial 10 = 2

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