# C programs

1. Palindrome for string

#include <stdio.h>
#include <string.h>
main()
{
char a[100], b[100];
printf("Enter the string to check if it is a palindrome\n");
gets(a);
strcpy(b,a);
strrev(b);
if( strcmp(a,b) == 0 )
printf("Entered string is a palindrome.\n");
else
printf("Entered string is not a palindrome.\n");
return 0;
}

2. Palindrome number in c
#include <stdio.h>
main()
{
int n, reverse = 0, temp;
printf("Enter a number to check if it is a palindrome or not\n");
scanf("%d",&n);
temp = n;
while( temp != 0 )
{
reverse = reverse * 10;
reverse = reverse + temp%10;
temp = temp/10;
}
if ( n == reverse )
printf("%d is a palindrome number.\n", n);
else
printf("%d is not a palindrome number.\n", n);
return 0;
}

3. Reverse a string using C programming
#include<stdio.h>
#include<string.h>
main()
{
char arr[100];
printf("Enter a string to reverse\n");
gets(arr);
strrev(arr);
printf("Reverse of entered string is \n%s\n",arr);
return 0;
}

4. Fibonacci Series c language
#include<stdio.h>
main()
{
int n, first = 0, second = 1, next, c;
printf("Enter the number of terms\n");
scanf("%d",&n);
printf("First %d terms of Fibonacci series are :-\n",n);
for ( c = 0 ; c < n ; c++ )
{
if ( c <= 1 )
next = c;
else
{
next = first + second;
first = second;
second = next;
}
printf("%d\n",next);
}
return 0;
}

5. Fibonacci series program in c using recursion
#include<stdio.h>
int Fibonacci(int);
main()
{
int n, i = 0, c;
scanf("%d",&n);
printf("Fibonacci series\n");
for ( c = 1 ; c <= n ; c++ )
{
printf("%d\n", Fibonacci(i));
i++;
}
return 0;
}
int Fibonacci(int n)
{
if ( n == 0 )
return 0;
else if ( n == 1 )
return 1;
else
return ( Fibonacci(n-1) + Fibonacci(n-2) );
}

6. Adding numbers in c using function
#include<stdio.h>
main()
{
long first, second, sum;
scanf("%ld%ld", &first, &second);
printf("%ld\n", sum);
return 0;
}
{
long result;
result = a + b;
return result;
}

7. Swapping of two numbers
Ans:
#include <stdio.h>

int main()
{
int x, y, temp;

printf("Enter the value of x and y\n");
scanf("%d%d", &x, &y);

printf("Before Swapping\nx = %d\ny = %d\n",x,y);

temp = x;
x    = y;
y    = temp;

printf("After Swapping\nx = %d\ny = %d\n",x,y);

return 0;
}

8. Odd or even
Ans:
#include<stdio.h>

main()
{
int n;

printf("Enter an integer\n");
scanf("%d",&n);

if ( n%2 == 0 )
printf("Even\n");
else
printf("Odd\n");

return 0;
}