What is the usage of the c++ substr function?

1 year ago
Ava Mitchell
1 minute

In C++, the substr function is used to extract a substring from a string. It is used as follows:

string substr (size_t pos, size_t len) const;

Description of Parameters:

  1. Start position: the starting position of the substring, indicating from which character of the original string to extract the substring.
  2. len: The length of the substring, indicating how many characters to extract.

Result:

  1. Return the substring extracted from the original string.

Example:

#include <iostream>
#include <string>

int main() {
    std::string str = "Hello, World!";
    std::string substr = str.substr(7, 5);
    std::cout << substr << std::endl; // 输出 "World"
    
    return 0;
}

In the example above, the substr function is used to extract 5 characters starting from the 7th character in the string “Hello, World!”, which is “World”. The extracted substring is then assigned to the substr variable and the result is outputted.

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