Suppose that, for some reason, you needed to write your own String class.^[78]

You might produce a class definition with several constructors such as these:

        class String {
          String();                // Creates an empty String of length 0
          String(const char* str); // Converts a char array to a String
          explicit String(int n);  // Creates length n String, filled 
                                   // with spaces
          ... other member functions - but not constructors ...
        };
        

Describe the String objects str1 and str2 produced by the following client code lines.

          ...
          String str1, str2;        // construct two empty strings
          str1 = "A";
          str2 = 'A';
          ...
        

Without explicit, the str2 assignment would produce a length 65 String filled with spaces.

That is because char 'A' would be promoted to the int 65 (the ASCII code for 'A') so that the third constructor could be (implicitly) called.