call of overloaded ‘swap(int&, int&)’ is ambiguous

The error message "call of overloaded 'swap(int&, int&)' is ambiguous" in C++ indicates that there are multiple possible functions or templates that can be called when trying to swap two integers using the swap function. This ambiguity occurs when there are different versions of the swap function available, and the compiler cannot determine which one to use based on the provided arguments.

To resolve this issue, we need to understand why the ambiguity arises and what steps can be taken to address it. The following steps explain the process:

  1. Check the arguments: Verify the arguments passed to the swap function. In this case, the arguments are of type int& (references to integers). Ensure that the arguments are correctly declared and initialized.

  2. Check for conflicting definitions: The ambiguity error typically occurs when there are conflicting definitions of the swap function. Check if there are multiple definitions or declarations of the swap function in the code.

  3. Check for namespaces: If there are multiple namespaces involved, the swap function might be defined in more than one namespace. This can lead to ambiguity. Ensure that the correct namespace is used when calling the swap function.

  4. Check for custom definitions: If you have defined your own swap function, it might conflict with the standard library swap function. This can result in ambiguity. Consider renaming your custom swap function to avoid conflicts.

  5. Explicitly specify the function: If there are multiple versions of the swap function available, you can explicitly specify which version to use by using the scope resolution operator ::. For example, if the standard library swap function is causing ambiguity, you can use std::swap to explicitly call the standard library version.

  6. Use using declaration: If there are multiple versions of the swap function and you want to use a specific one without explicitly specifying the scope, you can use a using declaration to introduce the desired version into the current scope. For example, using std::swap; will bring the swap function from the std namespace into the current scope.

By following these steps, you should be able to resolve the ambiguity error and successfully call the swap function in C++. Remember to review the specific context of your code to identify the cause of the ambiguity and apply the appropriate solution.