Remove prefix from a string in C++

This post will discuss how to remove the prefix from a string in C++.

The standard solution to remove part of a string is using the std::string::erase member function. It can be used as follows:

#include <iostream>

#include <string>

int main()

{

std::string str = "ThinkPad";

std::string prefix = "Think";

str.erase(0, prefix.length());

std::cout << str << std::endl; // Pad

return 0;

}

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To get the copy of the string with the prefix removed, we can use the std::string::substr function:

#include <iostream>

#include <string>

int main()

{

std::string str = "ThinkPad";

std::string prefix = "Think";

std::string result = str.substr(prefix.length());

std::cout << result << std::endl; // Pad

return 0;

}

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It is advisable to check whether a string starts with a prefix before removing it. This can be achieved using C++20 std::string.starts_with() or std::string::substr function.

#include <iostream>

#include <string>

int main()

{

std::string str = "ThinkPad";

std::string prefix = "Think";

std::string result = str.starts_with(prefix)? str.substr(prefix.size()): str;

std::cout << result << std::endl; // Pad

return 0;

}

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That’s all about removing the prefix from a string in C++.

Remove prefix from a string in C++

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