Strings in c++

• A string is a sequence of characters. C and C++ implement strings as arrays of char. The C++ language additionally supports string objects.
• In the C language, the only option is a char array.
• We use the term C string to refer to an array of characters as used in the C language. In this section, any mention of the term string refers to a C string.
• A string is an array of characters. A string literal is a sequence of characters enclosed within quotation marks, as in

std::cout << "How\n";

• The string word can hold 255 viable characters plus the null terminator. If the user types in relatively short words (length less than 255 characters), there is no problem.
• If at any time the user types in more characters than will fit in the word array, the executing program will have a problem.
• The problem is known as a buffer overrun. In the best case, buffer overruns lead to buggy programs.
• In the worst case, clever users can exploit buffer overruns to compromise software systems. Buffer overruns are always logic errors and you should take great care to avoid them.
• Strings are arrays of characters. The special character ' \0' (NUL) is used to indicate the end of a string.

Example

char name[4];

 main ()
 {
 name[0] = 'S';
 name[1] = 'a';
 name[2] = 'm';
 name[3] = '\0';
 return (0);
 }

• This creates a character array four elements long. Note that we had to allocate one character for the end-of-string marker.
• String constants consist of text enclosed in double quotes ("). You may have already noticed that we've used string constants extensively for output with the cout standard class.
• C++ does not allow one array to be assigned to another, so you can't write an assignment of the form:

name = "Sam"; // Illegal