sol1.c File Reference

Problem 1 solution More...

#include <stdio.h>

Include dependency graph for sol1.c:

Functions
int	main ()
	Main function. More...

Detailed Description

Problem 1 solution

An Efficient code to print all the sum of all numbers that are multiples of 3 & 5 below N.

Function Documentation

main()

int main

(

void

)

Main function.

{
    int t;
    printf("Enter number of times you want to try");
    scanf("%d", &t);
    while (t--)  // while t > 0, decrement 't' before every iteration
    {
        unsigned long long N, p = 0, sum = 0;
        printf("Enter the value of N ");
 
        scanf("%lld", &N);  // Take input of N from user
        p = (N - 1) / 3;
        sum = ((3 * p * (p + 1)) / 2);
 
        p = (N - 1) / 5;
        sum = sum + ((5 * p * (p + 1)) / 2);
 
        p = (N - 1) / 15;
        sum = sum - ((15 * p * (p + 1)) / 2);
        printf("%lld\n", sum);  // print the sum of all numbers that are
                                // multiples of 3 & 5 below N
    }
    return 0;
}