Cannot use string(size_t , char) constructor

I have a class Screen which has member content initialized using string(size_t, char) constructor.

  #include<iostream>
  #include <string>

    struct Screen{
        friend std::ostream& print(std::ostream& os,const Screen& screen);

        Screen() = default;
        Screen(std::size_t w, std::size_t h):width(w), height(h), content(w * h , ' '){}
        Screen(std::size_t w, std::size_t h, char c):width(w), height(h), content(w*h, c){}

    private:
        std::size_t width = 24;
        std::size_t height = 80;
        std::size_t cursor = 0;
        string content( (width * height), ' ');
    };

I tried declaring a string in similar way inside main but I get the same error, I am not able to figure out what am I doing wrong here.

structures.cpp:16:21: error: expected identifier before '(' token
     string content( (width * height), ' ');
                     ^
structures.cpp:16:28: error: expected ')' before '*' token
     string content( (width * height), ' ');
                            ^
structures.cpp:16:28: error: expected ')' before '*' token
structures.cpp:16:22: error: expected ';' at end of member declaration
     string content( (width * height), ' ');
                      ^
structures.cpp:16:30: error: expected ';' at end of member declaration
     string content( (width * height), ' ');