WAP to swap the values of two variables
Objective
Write a C++ program to swap the values of two variables using a function.
Algorithm / Approach
- Declare a
swap(int, int)function prototype. - Read two variables in
main()and print them. - Call the
swap(x, y)function, passing the variables. - Inside the function, swap the values using a temporary variable and print them.
main.cpp
#include<iostream>
using namespace std;
void swap(int, int);
int main( ){
int x,y;
cout<<"Enter X: ";
cin>>x;
cout<<"Enter Y: ";
cin>>y;
cout<<"\nBEFORE SWAP:\n";
cout<<"X = "<< x<<" and Y = "<< y;
swap(x,y);
return 0;
}
void swap(int x, int y){
int temp = x;
x = y;
y = temp;
cout<<"\n\nAFTER SWAP : \n";
cout<<"X= "<< x<<" and Y= "<< y;
}Expected Output
Enter X: 15 Enter Y: 20 BEFORE SWAP: X=15 and Y=20 AFTER SWAP: X=20 and Y=15
Explanation of the Program
- Functions allow you to break down your code into reusable, modular blocks.
- Note: This program demonstrates "Pass by Value". The
swapfunction receives completely independent *copies* of the variables. While the copies are successfully swapped inside the function, the original variables back inmain()remain completely unchanged!
Complexity
Time Complexity
O(1)
Space Complexity
O(1)
Common Mistakes
- Assuming "Pass by Value" will modify original variables. To actually swap the variables in main, you must use "Pass by Reference" (e.g.,
void swap(int &x, int &y)) or pointers.
