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CHRISTOPHER BARTHOLOMEW: Welcome back.

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In another video, we discussed the char data type in C which

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can be used to hold letters, numbers and special characters

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such as the question or exclamation mark.

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We know that an individual char has an ASCII value, which

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is an integer representation of the character.

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For example, capital letter A's ASCII value is 65.

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But in C, what do we use for actual words or sentences such

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as programming, or "C is beautiful?"

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The answer is a string--

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but to be more specific, it is a character string.

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A character string, or a string, is a sequence of one

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byte chars that are stored alongside

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each other in memory.

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And at the end of any character string in the C

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language, there's one additional byte that is

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allocated for a special character--

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backslash 0, which is the null termination character.

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The null termination character is a 1 byte char whose bits

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are all 0 and it is used to signal the end

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of a string in memory.

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This means whether you intend to initialize your string as

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the sentence "C is fun," or just the word "fun," at the

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end there will always be a null termination character

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indicating that the string has ended.

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To use a string in your program, it is recommended

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that you initialize your variable as this--

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chart star S equals open quote, your string, close

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quote, semicolon.

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In this variable definition, variable S points to the first

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character in our string, which is C. You see, because we now

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know the entire string is stored sequentially in memory,

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we can retrieve the string with no problems as we also

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know where it ends, too--

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the null termination character.

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So have fun.

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I'm Christopher Bartholomew, this is cs50.