C++ .swap()

In C++, the .swap() method for strings is used to exchange the contents of two strings efficiently. It is commonly used in scenarios like optimizing performance during reordering, implementing the copy-and-swap idiom in custom classes, or quickly clearing a string by swapping it with an empty one.

Syntax

string1.swap(string2);

Parameters:

• string2: Another std::string object whose contents will be swapped with string1.

Return value:

This method performs the swap in-place and does not return a value.

After calling the .swap() method, the contents of string1 and string2 are exchanged: string1 now holds the original contents of string2, and string2 holds the original contents of string1.

Example

In this example, the .swap() method is used to exchange the contents of two strings, a and b:

#include <iostream>
#include <string>

int main() {
  std::string a = "apple";
  std::string b = "banana";

  std::cout << "Before swap:\n";
  std::cout << "a = " << a << "\n";
  std::cout << "b = " << b << "\n";

  // Swap the contents of a and b
  a.swap(b);

  std::cout << "\nAfter swap:\n";
  std::cout << "a = " << a << "\n";
  std::cout << "b = " << b << "\n";

  return 0;
}

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The output for this will be:

Before swap:
a = apple
b = banana

After swap:
a = banana
b = apple

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Codebyte Example

In this codebyte example, .swap() is called on the place1 and place2 strings:

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