C Program To Calculate Sum of Natural Numbers Between Range using For Loop

Lets write a C program to calculate sum of all natural numbers between the user entered range of numbers, using for loop.

We check if the user has entered smaller number first and then the larger number. If not, we swap the numbers present in the variables min and max.

Related Read:
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Swap 2 Numbers Using a Temporary Variable: C

Video Tutorial: C Program To Calculate Sum of Natural Numbers Between Range using For Loop

Source Code: C Program To Calculate Sum of Natural Numbers Between Range using For Loop

 
#include<stdio.h>

int main()
{
    int min, max, temp, count, sum = 0;

    printf("Enter 2 positive numbers\n");
    scanf("%d%d", &min, &max);

    if(min > max)
    {
        temp = min;
        min  = max;
        max  = temp;
    }

    printf("\nNatural Numbers from %d to %d are:\n", min, max);

    for(count = min; count <= max; count++)
    {
        printf("%d\n", count);
        sum = sum + count;
    }

    printf("Sum of Natural Numbers from %d to %d is %d\n", min, max, sum);

    return 0;
}

Output 1:
Enter 2 positive numbers
5
10

Natural Numbers from 5 to 10 are:
5
6
7
8
9
10
Sum of Natural Numbers from 5 to 10 is 45

Output 2:
Enter 2 positive numbers
14
10

Natural Numbers from 10 to 14 are:
10
11
12
13
14
Sum of Natural Numbers from 10 to 14 is 60

Logic To Calculate Sum of Natural Numbers Between Range using For Loop

We ask the user to enter minimum and maximum number(i.e., the range) and we store it inside variable min and max. If value of min is greater than value of max, then we swap the values of min and max.

We initialize the variable count to min and iterate through the for loop until count value is less than or equal to value of max. We keep incrementing the value of count by 1 for each iteration of for loop.

Inside for loop we add the value of count to previous value of sum and once the control exits the for loop we display the value present in variable sum.

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