C++ String Error

Question

I got a code with an error: invalid conversion from 'const char*' to 'char'

std::string zipZap(const std::string& str){
    for (unsigned i = 0; i < str.length(); i++){
        if (str[i] == 'z'){
            if (str[i+2] == 'p'){
                str[i+1] = "";
            }
        }
    }
    return str;
}

Answer 1

const string cant be modified. If you want to modify the string remove const from it.

And also you are assigning string to char index of string string[i+1] = ""

Instead it should be string[i+1] = ' ' or string[i+1] = '\0'

Answer 2

const std::string& string

string is const, you cannot modify it like string[i+1] = "";