The function std::swap() is a built-in function in the C++ Standard Template Library (STL) which swaps the value of two variables.
Syntax:
swap(a, b)
Parameters:
The function accepts two mandatory parameters a and b which are to be swapped. The parameters can be of any data type.
Return Value:
The function does not return anything, it swaps the values of the two variables. Programs below illustrate the swap() function:
Time Complexity: O(1)
Space Complexity: O(1)
Program 1:
CPP
// C++ program for illustration of swap() function #include <bits/stdc++.h> using namespace std;
int main()
{ int a = 10;
int b = 20;
cout << "Value of a before: " << a << endl;
cout << "Value of b before: " << b << endl;
// swap values of the variables
swap(a, b);
cout << "Value of a now: " << a << endl;
cout << "Value of b now: " << b << endl;
return 0;
} |
Output
Value of a before: 10 Value of b before: 20 Value of a now: 20 Value of b now: 10
Program 2:
CPP
#include <bits/stdc++.h> using namespace std;
int main()
{ string a = "Geeks" ;
string b = "function" ;
cout << "Value of a before: " << a << endl;
cout << "Value of b before: " << b << endl;
swap(a, b);
cout << "Value of a now: " << a << endl;
cout << "Value of b now: " << b << endl;
return 0;
} |
Output
Value of a before: Geeks Value of b before: function Value of a now: function Value of b now: Geeks