# C Exercises: Calculate the sum of numbers from 1 to n

## C Recursion : Exercise-2 with Solution

Write a program in C to calculate the sum of numbers from 1 to n using recursion.
Test Data :
Input the last number of the range starting from 1 : 5
Expected Output :

```The sum of numbers from 1 to 5 :
15
```

C Code:

```#include<stdio.h>

int sumOfRange(int);

int main()
{
int n1;
int sum;
printf("\n\n Recursion : calculate the sum of numbers from 1 to n :\n");
printf("-----------------------------------------------------------\n");

printf(" Input the last number of the range starting from 1 : ");
scanf("%d", &n1);

sum = sumOfRange(n1);
printf("\n The sum of numbers from 1 to %d : %d\n\n", n1, sum);

return (0);
}

int sumOfRange(int n1)
{
int res;
if (n1 == 1)
{
return (1);
} else
{
res = n1 + sumOfRange(n1 - 1); //calling the function sumOfRange itself
}
return (res);
}
```

Flowchart :

C Practice online:

```#include<stdio.h>

int sumOfRange(int);

int main()
{
int n1;
int sum;
printf("\n\n Recursion : calculate the sum of numbers from 1 to n :\n");
printf("-----------------------------------------------------------\n");

printf(" Input the last number of the range starting from 1 : ");
scanf("%d", &n1);

sum = sumOfRange(n1);
printf("\n The sum of numbers from 1 to %d : %d\n\n", n1, sum);

return (0);
}

int sumOfRange(int n1)
{
int res;
if (n1 == 1)
{
return (1);
} else
{
res = n1 + sumOfRange(n1 - 1); //calling the function sumOfRange itself
}
return (res);
}
```

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