Question and Answer
Q What is a string? How do you know its length?
A In C, a string is a character array terminated by a null character. Whenever a null character is encountered in a string, functions, such as puts() or strcpy(), will stop printing or copying the next character.
The C function strlen() can be used to measure the length of a string. If it is successful, the strlen() function returns the total number of bytes taken by the string; however, the null character in the string is not counted.
Q What are the main differences between a string constant and a character constant?
A A string constant is a series of characters enclosed by double quotes, while a character constant is a single character surrounded by single quotes. The compiler will append a null character to the array that is initialized with a string constant. Therefore, an extra byte has to be reserved for the null character. On the other hand, a character constant takes only 1 byte in the memory.
Q Does the gets() function save the newline character from the standard input stream?
A No. The gets() function keeps reading characters from the standard input stream until a newline character or end-of-file is encountered. Instead of saving the newline character, the gets() function appends a null character to the array that is referenced by the argument to the gets() function.
Q What types of data can the scanf() function read?
A Depending on the format specifiers indicated in the function, the scanf() function can read various types of data, such as a series of characters, integers, or floating-point numbers. Unlike gets(), scanf() stops reading the current input item (and moves to the next input item, if there is one) when it encounters a space, a newline, a tab, a vertical tab, or a form feed.
