In this post, we will learn how to calculate the sum of natural numbers using C++ Programming language.
This program asks the user to enter a maximum natural number upto which the user wants the sum. Then, it calculate the sum of natural numbers using the following approaches:
- Using For Loop
- Using While Loop
- Using Do While Loop
So, without further ado, let’s begin this tutorial.
C++ Program to Calculate the Sum of Natural Numbers
// C++ Program to Calculate the Sum of Natural Numbers
#include <iostream>
using namespace std;
int main(){
int num, sum = 0;
// Asking for input
cout << "Enter the maximum number: ";
cin >> num;
// Calculating sum using for loop
for (int i =1; i <= num; i++){
sum = sum + i;
}
// Displaying output
cout << "Sum of natural numbers: " << sum << endl;
return 0;
}
Output
Enter the maximum number: 25
Sum of natural numbers: 325
How Does This Program Work ?
int num, sum = 0;
In this program, we have declared two integer data type variables named num and sum, where the sum variable has assigned a value of 0.
// Asking for input
cout << "Enter the maximum number: ";
cin >> num;
Now, the user is asked to enter a maximum number upto which the user wants the sum. This value gets stored in the num named variable.
// Calculating sum using for loop
for (int i =1; i <= num; i++){
sum = sum + i;
}
We initiate the for loop with the i = 1 and the value of i keeps incrementing by 1 until the value of i is less than or equal to num.
For every iteration, the sum variable becomes sum = sum + 1.
Suppose, the user enters the maximum number 3.
- Then, After the 1st iteration sum = sum + i = 0 + 1 = 1.
- After the 2nd iteration sum = sum + i = 1 + 2 = 3.
- And after the 3rd iteration, sum = sum + i = 3 + 3 = 6.
After that i > num, so the loop terminates and we get sum = 6.
// Displaying output
cout << "Sum of natural numbers: " << sum << endl;
The sum calculated in the previous step is displayed on the screen using the cout statement.
C++ Program to Calculate the Sum of Natural Numbers Using While Loop
// C++ Program to Calculate the Sum of Natural Numbers Using While Loop
#include <iostream>
using namespace std;
int main(){
int num, sum = 0;
// Asking for input
cout << "Enter the maximum number: ";
cin >> num;
int i = 1;
while (i <= num){
sum = sum + i;
i++;
}
// Displaying output
cout << "Sum of natural numbers: " << sum << endl;
return 0;
}
Output
Enter the maximum number: 3 Sum of natural numbers: 6
C++ Program to Calculate the Sum of Natural Numbers Using Do While Loop
// C++ Program to Calculate the Sum of Natural Numbers Using Do While Loop
#include <iostream>
using namespace std;
int main(){
int n, i = 1, sum = 0;
// Asking for input
cout << "Enter the maximum number: ";
cin >> n;
// Calculating the sum using do-while loop
do {
sum = sum + i;
i++;
}
while (i <= n);
// Displaying output
cout << "Sum of natural numbers: " << sum << endl;
return 0;
}
Output
Enter the maximum number: 10
Sum of natural numbers: 55
Conclusion
I hope after going through this post, you understand how to calculate the sum of natural numbers using C++ Programming language.
If you have any doubt regarding the program, then contact us in the comment section. We will be delighted to assist you.
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