如果要替换的句子带有"+“号，则C++替换字符串函数不起作用

#include <iostream>
#include <string>

void replaceString(std::string& str, const std::string& oldStr, const std::string& newStr) {
    size_t pos = 0;
    while ((pos = str.find(oldStr, pos)) != std::string::npos) {
        str.replace(pos, oldStr.length(), newStr);
        pos += newStr.length();
    }
}

int main() {
    std::string sentence = "如果要替换的句子带有+号，则C++替换字符串函数不起作用";
    std::string oldStr = "+";
    std::string newStr = "plus";

    replaceString(sentence, oldStr, newStr);

    std::cout << sentence << std::endl;

    return 0;
}