Swap numbers

In this program, int a,b,c statement declares 3 variables named as a,b & c . The 2 values
are entered by user because of scanf statement & stored in a & b which are the no. to be

swapped . Now, c variable is  a temporary variable to store 1st value . Using a = b, 2nd variable

value is now stored in 1st variable then c which stores value of 1st variable is assigned to 2nd 

variable & hence swapping is done 
For more information & explanation of this program click here..

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Program to swap using third variable.

#include<stdio.h>

#include<conio.h>

void main()

{ int a,b,c;

clrscr();

printf("\nprogram to swap 2 no.s");

printf("\n\nenter value of a :");

scanf("%d",&a);

printf("enter value of b :");

scanf("%d",&b);

c = a;

a = b;

b = c;

printf("\n now value of a = %d",a);

printf("\n now value of b = %d",b);

getch();

}