// Program to output the sum of first 'n' numbers


// Header file
#include <iostream.h>


// Function Prototype
int SumOfNnumbers (int num);


// Main function
int main (void)
{
    int num;   // Variable Declaration
   
    // Read the number 'n' from the user
    cout << "Input a number: ";
    cin >> num;

    // Compute and print the sum of first n numbers
    cout << "Sum of first " << num << " numbers: " << SumOfNnumbers(num) << endl;

    // return success
    return 0;
}


// Function Definition of SumOfNnumbers
int SumOfNnumbers (int num)
{
    // local variable declaration
    int n;
    int sum = 0;

    // statements
    for (n = 1; n <= num; n++)
        sum = sum + n;

    // return result
    return sum;
}