Program 17 - CSU1128 - CSE 2026 - Shoolini University

Program to calculate and print the sum of all numbers between the numbers that the user chooses. Example 1 to 100

Explanation

The program calculates and prints the sum of all numbers between two numbers input by the user.

Header

The code begins with including the standard input-output header file using #include <stdio.h>.

Variable Declaration

The main() function is defined, and three integer variables d, m, and j are declared. Variable j is initialized to 0 to store the sum of the numbers.

Program Description

The program prints a description message for the user to understand its functionality.

User Input

The user is prompted to enter two numbers between which they want to find the sum of all the numbers. The input is read using scanf("%d %d", &d, &m);.

Swapping Logic

If the user enters the larger number first, a conditional statement swaps the values of d and m to ensure d is always the smaller number:

if (d > m): Checks if d is greater than m.
int o = d;: Temporarily stores d in o.
d = m;: Assigns the value of m to d.
m = o;: Assigns the stored value in o to m.

Sum Calculation

The program calculates the sum of all numbers between d and m using a while loop:

while (d <= m): Continuously checks if d is less than or equal to m.
j += d;: Adds the current value of d to j.
d++;: Increments d by 1.

Program End

The program prints the final sum stored in j and ends with printf("\n"); to print a new line and return 0; to indicate successful execution.

Code

                    
/*
 * -----------------------------------------------------------
 * Logic Building with Computer Programming (CSU1128)
 * Instructor: Dr. Pankaj Vaidya | Author: Divya Mohan
 * 
 * This code is a part of the educational initiative by dmj.one
 * with aim of empowering and inspiring learners in the field of
 * Computer Science and Engineering through the respective courses.
 * 
 * (c) 2022, Divya Mohan for dmj.one. All rights reserved.
 * -----------------------------------------------------------
 */

#include <stdio.h>
int main()
{
    int d, m, j = 0;
    printf("\n\n Program to calculate and print the sum of all numbers between the numbers that the user chooses. Example 1 to 100. \n\n");

    printf("Enter two numbers between which you want to find the sum of all the numbers - (Example: 2 100) - and press enter: ");
    scanf("%d %d", &d, &m);

    // if loop to swap max number if user enters a bigger number first.
    if (d > m)
    {
        int o = d;
        d = m;
        m = o;
    }

    printf("\nSum of all the numbers between %d and %d is ", d, m);
    while (d <= m)
    {
        j += d;
        d++;
    }
    printf("%d\t", j);
    printf("\n");
    return 0;
}

Output

Program to calculate and print the sum of all numbers between the numbers that the user chooses. Example 1 to 100.

Enter two numbers between which you want to find the sum of all the numbers - (Example: 2 100) - and press enter: 22 34
Sum of all the numbers between 22 and 34 is 364