Program to Swap two strings in C++

There are three tricks through which we swap the strings in C++;

Three Character Array Method
Three string method
Inbuilt swap function

Three Character Array Method

In this method,

We copy the contents of the first string to a temporary array.
The, we copy the contents of the second array in the first character array.
Next, we copy the contents of the temporary array to second character array.

Advantage:

We can use this method to reverse the contents of a numeric array too.
We do not need to include string library.

Disadvantage:

High time complexity due to many loops(due to copying array contents).
Very tedious time-consuming.

Three string method

In this method, We use the same technique as above, but we use strings here instead of character arrays.

We include the string library, and make three objects of String class.
We use the inbuilt function strcpy() and follow the naïve method of swapping.

Code:

#include <iostream>
#include <cstring> //string library
using namespace std;
int main() {
int n; //length of string
cin>>n;
char s1[n];
char s2[n];
char s3[n]; //temporary string
//Input String 1
cin>>s1;
//Input String 2
cin>>s2;
strcpy(s3,s1); //copy contents of s1 in s3
strcpy(s1,s2);  // similar to  s1=s2
strcpy(s2,s3);
cout<<s1<<"\n";
cout<<s2;
return 0;
}

Advantage:

It is faster than the previous method.

Disadvantage:

We need to use three strings, which is a waste of memory.

Inbuilt swap function

In this method, we use the inbuilt swap function to perform the task.

We include the string library and make two string objects.
Then, we make use of swap() function and output the strings.

Code:

#include <iostream>
#include <string>
using namespace std;
int main() {
string str1;
string str2;
//input string 1
cin&gt;&gt;str1;
//input string 2
cin&gt;&gt;str2;

str1.swap(str2); //swap contents of str1 and str2
cout&lt;&lt;str1&lt;&lt;"\n";
cout&lt;&lt;str2;

return 0;
}

Advantage:

It is the fastest of all.
It uses only two strings to execute the task.

Three Character Array Method

Three string method

Inbuilt swap function