Swapping of two numbers in c
#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; } Swapping of two numbers without third variable You can also swap two numbers without using temp or temporary or third variable. In that case c program will be as shown :-
#include <stdio.h> int main() { int a, b; printf("Enter two integers to swap\n"); scanf("%d%d", &a, &b); a = a + b; b = a - b; a = a - b; printf("a = %d\nb = %d\n",a,b); return 0; } To understand above logic simply choose a as 7 and b as 9 and then do what is written in program. You can choose any other combination of numbers as well. Sometimes it's a good way to understand a program.
Swap two numbers using pointers #include <stdio.h> int main() { int x, y, *a, *b, 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); a = &x; b = &y; temp = *b; *b = *a; *a = temp; printf("After Swapping\nx = %d\ny = %d\n", x, y); return 0; } Swapping numbers using call by reference In this method we will make a function to swap numbers.
#include <stdio.h> void swap(int*, int*); int main() { int x, y; printf("Enter the value of x and y\n"); scanf("%d%d",&x,&y); printf("Before Swapping\nx = %d\ny = %d\n", x, y); swap(&x, &y); printf("After Swapping\nx = %d\ny = %d\n", x, y); return 0; } void swap(int *a, int *b) { int temp; temp = *b; *b = *a; *a = temp; } C programming code to swap using bitwise XOR #include <stdio.h> int main() { int x, y; scanf("%d%d", &x, &y); printf("x = %d\ny = %d\n", x, y); x = x ^ y; y = x ^ y; x = x ^ y; printf("x = %d\ny = %d\n", x, y); return 0; } The code to swap two variables using macro expansions
Code: C
#include<stdio. h> #include<conio. h> #define SWAPE (x,y ) int t;t=x;x=y;y=t; main (){ int a,b; printf("\n Enter two number"); scanf ("%d%d",&a,&b ); printf("\n Before swaping the Value of a=%d and b=%d",a,b ); SWAPE (a,b ); printf("\n After swap value of a=%d and b=%d",a,b ); return 0; }
//Code for swapping two numbers without using temp variable
Code: CPP
#include <iostream>
using namespace std;
int main ()
{
int a = 10;
int b = 5;
cout << "before swap: a = " << a << " b = " << b << endl;
//Swapping numbers without using a temp var : method1
a = a ^ b;
b = b ^ a;
a = a ^ b;
cout << "after swap using method1: a = " << a << " b = " << b << endl;
//Swapping numbers without using a temp var : method2
a = a + b;
b = a - b;
a = a - b;
cout << "after swap using method2: a = " << a << " b = " << b << endl;
return 0;
}
the below logic also works as follows for swapping of nos without external variable introduction
Code:
main()
{
int a,b;
printf("enter the nos");
scanf("%d %d",&a,&b);
printf("nos before swapping a=%d ,b=%d", a,b);
a=a*b;
b=a/b;
a=a/b;
printf("nos after swapping a=%d ,b=%d", a,b);
}
| 
