How do you swap 2 variables without using third variable?

Answer 1

void main() { int a,b; clrscr(); printf("\n\n\t\tenter any two nos..."); scanf("%d%d",&a,&b); a=a+b; b=a-b; a=a-b; printf("\n\n\t\tvalue of a=",a); printf("\n\n\t\tvalue of b=",b); getch(); }

Answer 2

Use the bitwise XOR assignment operator (^=) three times, alternating the operands each time.

Note that the operands must be distinct -- they may be the same value, but they must be different variables (in completely different memory locations). XORing a variable with itself yields the value zero, so if x=1, x^=x would make x=0, thus the "swap" fails.

The following code demonstrates the algorithm.

#include <iostream>

int main()

{

int x = 42;

int y = 67;

printf( "Before:\tx=%d, y=%d\n", x, y );

x ^= y;

y ^= x;

x ^= y;

printf( "After:\tx=%d, y=%d\n", x, y );

return( 0 );

}

Answer 3

a=b+a;

b=a-b;

a=a-b;

with 3rd variable

If a=10

b=20

c=a; (now c=10 and a is empty)

a=b; ( b's value assign to a=20)

b=c; (now c assign value to b=10)

now it is swapped

a=20

b=10

Answer 4

Let us take a=40,b=50.Now after swapping,we should get the output as a=50,b=40.

main()

{

int a=40,b=50;

a=a+b;

b=a-b;

a=a-b;

printf("a=%d,b=%d",a,b);

}

Answer 5

In C++, the coding is :

#include <iostream.h>

#include <conio.h>

void main()

{

int a,b;

cout<<"type the value of a and b ";

cin>>a>>b;

a=a+b;

b=a-b;

a=a-b;

cout<<"after swapping the values are :";

cout<<a<<"\t"<<b<<"\n";

getch();

}

Answer 6

1)

num1 = num1 + num2;

num2 = num1 - num2;

num1 = num1 - num2;

Enter Number 1: 20

Enter Number 2:

10

After swapping, num1=10 and num2=20

2)

x -= y;

y += x; // y becomes x

x = (y - x); // x becomes y

3)

x = x*y;

y = x / y;

x = x / y;