C++ || Snippet – How To Swap Two Numbers Without Using A Third “Temporary” Variable

July 23, 2012 admin No comments

The following are three programs which demonstrates how to swap two numbers without using a third “temporary” variable.

Why would anyone want to swap two numbers without utilizing a third variable? There is no real reason to do so other than the fact that exercises such as these are typically used as programming assignments/interview questions. This is a technique that’s rarely ever practical in a real world setting, but it is still an interesting task nonetheless.





		
		
			#1 - Using Simple Math
			
C++
			
			#include <iostream>
using namespace std;

int main() 
{
	// declare variables
	int x = 0;
	int y = 0;

	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;

	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using simple math
	x = x+y;
	y = x-y;
	x = x-y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
using namespace std;
 
int main() 
{
	// declare variables
	int x = 0;
	int y = 0;
 
	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
 
	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using simple math
	x = x+y;
	y = x-y;
	x = x-y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/

SAMPLE OUTPUT:

Please enter two numbers: 7 28
Item #1 = 7 Item #2 = 28 Switching the numbers..
Item #1 = 28 Item #2 = 7





		
		
			#2 - Using The XOR Swap Algorithm
			
C++
			
			#include <iostream>
using namespace std;

int main() 
{
	// declare variables
	int x = 0;
	int y = 0;

	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;

	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using the xor swap algorithm
	x ^= y;
	y ^= x;
	x ^= y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
using namespace std;
 
int main() 
{
	// declare variables
	int x = 0;
	int y = 0;
 
	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
 
	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using the xor swap algorithm
	x ^= y;
	y ^= x;
	x ^= y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/

SAMPLE OUTPUT:

Please enter two numbers: 5 12453
Item #1 = 5 Item #2 = 12453 Switching the numbers..
Item #1 = 12453 Item #2 = 5





		
		
			#3 - Using The In-Built Swap Function
			
C++
			
			#include <iostream>
#include <algorithm>
using namespace std;

int main() 
{
	// declare variables
	int x = 0;
	int y = 0;

	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;

	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using the in-built swap function
	swap(x, y);

	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/
			
				
					
				
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						#include <iostream>
#include <algorithm>
using namespace std;
 
int main() 
{
	// declare variables
	int x = 0;
	int y = 0;
 
	// get data
	cout <<"Please enter two numbers: ";
	cin >> x >> y;
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
 
	cout <<"nSwitching the numbers..n";
	
	// switch the numbers using the in-built swap function
	swap(x, y);
 
	cout <<"nItem #1 = "<<x<<endl;
	cout <<"Item #2 = "<<y<<endl;
	
	return 0;
}// http://programmingnotes.org/

SAMPLE OUTPUT:

Please enter two numbers: 2132 6547546
Item #1 = 2132 Item #2 = 6547546 Switching the numbers..
Item #1 = 6547546 Item #2 = 2132

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Posted in: Advanced, C++, C++, Snippets Tags: c++, input, Output

C++ || Snippet – How To Swap Two Numbers Without Using A Third “Temporary” Variable

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