# Palindrome numbers program in C

Swap number means interchanging the value of two variables. if the value of variable a = 10 and b = 20 then after swapping the value of variable a will be 20 and b will be 10. In this article we will swap numbers using various way.

## Swap numbers using a third variable

In this program we will swap two number using a third variable called temp. We will use this temp variable to swap number as follows.

``````// swap number using a temp variable
#include <stdio.h>
int main(){
int a, b, temp;

printf("Enter first integer : ");
scanf("%d", &a);
printf("Enter second integer : ");
scanf("%d", &b);

temp = a;
a = b;
b = temp;

printf("\nAfter Swapping the numbers are\n\n");
printf("First integer is = %d\n", a);
printf("Second integer is = %d\n", b);

return 0;
}``````

### Output of the swap numbers program ## Swap numbers without a temp variable

In this program we will will not use any temp variable to swap two numbers. Program for swapping of two numbers using C without a third variable is given bellow.

``````// swapping two numbers without a temp variable
#include <stdio.h>
int main(){
int firstNumber, secondNumber;

printf("Enter first number : ");
scanf("%d", &firstNumber);
printf("Enter second number : ");
scanf("%d", &secondNumber);

firstNumber = firstNumber + secondNumber;
secondNumber = firstNumber - secondNumber;
firstNumber = firstNumber - secondNumber;

printf("\nAfter swapping\n\n");
printf("First number = %d\n", firstNumber);
printf("Second number = %d\n", secondNumber);
return 0;
}``````

### See output of program ## Swap number using bitwise operator

``````// swap numbers using bitwise operator in C
#include <stdio.h>
int main(){
int i, j;

printf("Enter first number here : ");
scanf("%d", &i);
printf("Enter second number here : ");
scanf("%d", &j);

printf("\nBefore swapping i = %d and j = %d\n", i, j);

i = i ^ j;
j = i ^ j;
i = i ^ j;

printf("\nAfter swapping i = %d and j = %d\n", i, j);

return 0;
}``````

### Output of program:

``````Enter first number here : 34
Enter second number here : 67

Before swapping i = 34 and j = 67

After swapping i = 67 and j = 34``````

## Swap two numbers using pointer in C

``````// swap numbers using pointer in C
#include <stdio.h>
int main(){
int temp, m, n, *x, *y;

printf("Enter number 1 : ");
scanf("%d", &m);
printf("Enter number 2 : ");
scanf("%d", &n);

printf("\nBefore Swapping number 1 = %d and number 2 = %d\n\n", m, n);

x = &m;
y = &n;

temp = *y;
*y   = *x;
*x   = temp;

printf("\nAfter Swapping number 1 = %d and number 2 = %d\n\n", m, n);

return 0;
}``````

### Output of swap number program:

``````Enter number 1 : 54
Enter number 2 : 89

Before Swapping number 1 = 54 and number 2 = 89

After Swapping number 1 = 89 and number 2 = 54

Process returned 0 (0x0)   execution time : 7.346 s
Press any key to continue.``````

## Swap two numbers using function in C

``````// swap numbers using fuction in C
#include <stdio.h>

void swapNumbers(int *x, int *y){     //Swap function
int temp;

temp  = *y;
*y = *x;
*x = temp;
}

int main(){
int a, b;

printf("Enter the value of a : ");
scanf("%d",&a);
printf("Enter the value of b : ");
scanf("%d",&b);

printf("\nBefore Swapping value of a = %d and b = %d\n\n", a, b);

swapNumbers(&a, &b);

printf("\nAfter Swapping value of a = %d and b = %d\n\n", a, b);

return 0;
}``````

### program output: Previous pagePalindrome numbers

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