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Characters. Character Data char data type – Represents one character – char literals indicated with ' '

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Presentation on theme: "Characters. Character Data char data type – Represents one character – char literals indicated with ' '"— Presentation transcript:

1 Characters

2 Character Data char data type – Represents one character – char literals indicated with ' '

3 Char vs String Char – One character – literals use ' ' String – 0+ characters – literals use " "

4 Character Data char is integer data type – 1 byte of space : 256 values – Assumed to represent characters

5 Chars as Integers Integers understood as ASCII codes – http://www.ascii-code.com/ http://www.ascii-code.com/ Can store integers as chars

6 Chars And Math Doing math – char converted to an int:

7 Chars And Math Adding/subtracting and cast back to character shifts char:

8 Letter Number Identify letter of alphabet: 'f' – 'a' + 1 102 – 97 + 1 5 + 1

9 Random Char Generate random char: – Make number 0-25 – Add to 'a'

10 Comparisons Chars compare like other numbers:

11 But Capitals different than lower case: – lower case is "greater"

12 Why is this broken? This prints nothing:

13 Why is this broken? This prints nothing: '3' is char 51 on ASCII chart if( 51 == 3 )

14 Fixed This works:

15 Special Chars Some characters hard to represent – return, tab, ' Escape sequences used to represent them – \ means next char is special: '\t' : tab char '\'' : ' char

16 Escape Codes Common codes:

17 Escape Codes Used in strings and as chars:

18 Case Conversion Convert lower to upper: – Subtract 'a' to find letter number – Add that amount to 'A'

19 Char Functions library has char related functions: – http://www.cplusplus.com/reference/cctype/ http://www.cplusplus.com/reference/cctype/ – all return int is… interpret as boolean to… interpret as char

20 Conversion 2 More readable conversion:

21 Conversion 3 toupper / tolower do their own sanity checks


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