## C Program to Find the Sum of Natural Numbers using Recursion

Code:

```#include <stdio.h>
int Sum(int x);
int Sum(int x)
{
if (x != 0)
return x + Sum(x - 1);
else
return x;
}
int main()
{
int number;
printf("Enter a number: ");
scanf("%d", &number);
printf("Sum of natural numbers is %d\n", Sum(number));
return 0;
}```

Output:

```Enter a number: 5
Sum of natural numbers is 15```

## C Program to Find Factorial of a Number Using Recursion

Code:

```#include <stdio.h>
long int Fact(int n);
long int Fact(int n)
{
if (n >= 1)
return n * Fact(n - 1);
else
return 1;
}
int main()
{
int n;
printf("Enter a number: ");
scanf("%d", &n);
printf("Factorial is %ld\n", Fact(n));
return 0;
}
```

Output:

```Enter a number: 5
Factorial is 120```

## C Program to Find G.C.D Using Recursion

Code:

```#include <stdio.h>
int GCD(int number1, int number2);
int GCD(int number1, int number2)
{
if (number2 != 0)
return GCD(number2, number1 % number2);
else
return number1;
}
int main()
{
int number1, number2;
printf("Enter first number: ");
scanf("%d", &number1);
printf("Enter second number: ");
scanf("%d", &number2);
printf("G.C.D is %d\n", GCD(number1, number2));
return 0;
}
```

Output:

```Enter first number: 8
Enter second number: 4
G.C.D is 4```

## C program to Reverse a Sentence Using Recursion

Code:

```#include <stdio.h>
void Rev();
void Rev()
{
char ch;
scanf("%c", &ch);
if (ch != '\n')
{
Rev();
printf("%c", ch);
}
}
int main()
{
printf("Enter sentence: ");
Rev();
printf("\n");
return 0;
}
```

Output:

```Enter sentence: Welcome To Codedec
cededoC oT emocleW```

## C program to calculate the power using recursion

Code:

```#include <stdio.h>
int power(int number1, int number2);
int power(int A, int n)
{
if (n != 0)
return (A * power(A, n - 1));
else
return 1;
}
int main()
{
int A, n, value;
printf("Enter a number: ");
scanf("%d", &A);
printf("Enter power value: ");
scanf("%d", &n);
value = power(A, n);
printf("Desired value is %d\n", value);
return 0;
}
```

Output:

```Enter a number: 5
Enter power value: 3
Desired value is 125```