How to swap without third variable?

A variable is a named location in memory that is used to store data which can be modified in a program. Let us see how to swap two variables without using third variable. This can be done in number of namely

By using arithmetic operators

By using Bitwise operators

By using Pointers Concept and so on

Let us see one of the method namely by using arithmetic operators.
Consider 2 variables say x=50 and y=70 and let us see how to swap the value of two variables that is make x=70 and y=50 without using third variable. This can be done by using following arithmetic operations namely

x= x + y

y= x - y

x= x - y

Which gives

x= x + y gives x= 70 + 50 an so x is equal to 120

y= x - y gives y = 120 - 70 which makes the value of y as 50

x= x - y gives x= 120 - 50 and thus value of x becomes 70

Thus value of x and y gets swapped without using third variable and the whole program is given below:

main()

{

int x=50,y=70;

x= x + y;

y= x - y;

x= x - y;

printf(“x=%d y=%d”, x,y);

}

This program gives output as
x=70 y=50

GeekAdmin
Profile Answers by GeekAdmin Questions by GeekAdmin
Jul 2nd, 2006
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sunithachenna
Profile Answers by sunithachenna Questions by sunithachenna

Apr 25th, 2007

u can also get the answer by writing
a=a^b;
b=a^b;
a=a^b; also

mikerich135
Profile Answers by mikerich135 Questions by mikerich135

Jun 23rd, 2007

You can also do it by multiplication and division,
x=x*y
y=x/y
x=x/y

Ramya Shetty

Nov 11th, 2015

a and b are two variables ; Following code will swap both number and string inputs
a = Inputbox("Enter a")
b = Inputbox("Enter b")
a = a + b
b = left(a,(instr(a,b)-1))
a = Right(a,(len(a)-len(b)))
msgbox "b ="&b
msgbox "a = "&a