How Can I Replace Parts of a String in C ?

Replacing a String Segment with a New String

In C , replacing a part of a string with another string requires a combination of operations. While some libraries offer a dedicated replace() function for direct replacements, here's how you can approach it using standard C functions:

Using find() and replace() Functions

The find() function locates the position of a substring within a string. By combining this with the replace() function, which replaces a specified range with another string, you can effectively replace a part of the string:

bool replace(std::string& str, const std::string& from, const std::string& to) {
    size_t start_pos = str.find(from);
    if(start_pos == std::string::npos)
        return false;
    str.replace(start_pos, from.length(), to);
    return true;
}

std::string string("hello $name");
replace(string, "$name", "Somename");

This approach replaces the first occurrence of the substring "$name" with "Somename."

Replacing All Occurrences with replaceAll

To replace all occurrences of a substring, you can extend the replace() method to search for and replace multiple instances within the string:

void replaceAll(std::string& str, const std::string& from, const std::string& to) {
    if(from.empty())
        return;
    size_t start_pos = 0;
    while((start_pos = str.find(from, start_pos)) != std::string::npos) {
        str.replace(start_pos, from.length(), to);
        start_pos += to.length(); // Adjust start position if 'to' contains 'from'
    }
}

This function performs a successive replacement of all occurrences of the substring "from" with the string "to" within the given string.

The above is the detailed content of How Can I Replace Parts of a String in C ?. For more information, please follow other related articles on the PHP Chinese website!