string of Cpp

The last character of every string is the null character. This character, written \0, is the character with ASCII code 0, and it serves to mark the string’s end.
The way to create a string in C++ is like that:

char bird[10] = “Mr. Cheeps”;// the \0 is understood
char fish[] = “Bubbles”;     // let the compiler count

If you want to indicate the length of the string,that you should make sure the array is large enough to hold all the characters of the string, including the null character.

char shirt_size = “S”;       // illegal type mismatch
Because of the "S" is just a string which have a ending char '\0', that you can't assign a char array to a char.

The problem lies with how cin determines when you’ve finished entering a string. You can’t enter the null character from the keyboard, so cin needs some other means for locating the end of a string. The cin technique is to use whitespace—spaces, tabs, and newlines—to delineate a string.  

you need a line-oriented method instead of a word-
oriented method. You are in luck, for the iostream class, of which cin is an example, has some line-oriented class member functions: getline() and get(). Both read an entire input line—that is, up until a newline character. However, getline() then discards the newline character,whereas get() leaves it in the input queue.

Because the first call leaves the newline character in the input queue, that newline character is the first character the second call sees. Thus, get() concludes that it’s reached the end of line without having found anything to read. Without help, get() just can’t get past that newline character.
The get() function will leave the '\n' char to the queue of the input, thus the get() function that suppose to get a string after a string just get one, will get noting.

then you should add a get() after where there must be a 'Enter'.