Semiconductor & Computer Engineering
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Difference between revisions of "c/ctype.h"
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| − | {{ | + | {{c title|<ctype.h> Header}}{{C Standard Library}} |
| − | {{C Standard Library}} | ||
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The '''<ctype.h> header''' is part of the [[standard library]] of the [[C programming language]] that declares several functions useful for classifying and mapping characters. | The '''<ctype.h> header''' is part of the [[standard library]] of the [[C programming language]] that declares several functions useful for classifying and mapping characters. | ||
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== Functions == | == Functions == | ||
| − | All functions in this header take a single argument of type '''int''' which should be representable as an '''unsigned char''' or be equal to the value of the macro ''' | + | All functions in this header take a single argument of type '''{{C|data types#Signed Integer Types|int}}''' which should be representable as an '''{{C|data types#Character Types|unsigned char}}''' or be equal to the value of the macro '''{{C|EOF}}'''. All other values result in ''[[undefined behavior]]''. |
Functions in this header falls under two categories: | Functions in this header falls under two categories: | ||
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{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
| − | ! Function Prototype | + | ! Function Prototype !! Description !! Since |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isalnum|int isalnum(int c);}} || Checks if c is alphanumeric. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isalpha|int isalpha(int c);}} || Checks if c is alphabetic. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isblank|int isblank(int c);}} || Checks if c is blank. || [[C99]] |
|- | |- | ||
| − | | | + | | {{C|ctype.h/iscntrl|int iscntrl(int c);}} || Checks if c is a control character. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isdigit|int isdigit(int c);}} || Checks if c is a decimal digit. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isgraph|int isgraph(int c);}} || Checks if c has a graphical representation. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/islower|int islower(int c);}} || Checks if c is a lowercase letter. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isprint|int isprint(int c);}} || Checks if c is printable. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/ispunct|int ispunct(int c);}} || Checks if c is a punctuation character. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isspace|int isspace(int c);}} || Checks if c is a white-space character. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isupper|int isupper(int c);}} || Checks if c is an uppercase letter. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/isxdigit|int isxdigit(int c);}} || Checks if c is a hexadecimal digit. || {{C|C89}} |
|} | |} | ||
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! Function Prototype !! Description !! Since | ! Function Prototype !! Description !! Since | ||
|- | |- | ||
| − | | | + | | {{C|ctype.h/tolower|int tolower(int c);}} || Converts an uppercase letter to a corresponding lowercase letter. || {{C|C89}} |
|- | |- | ||
| − | | | + | | {{C|ctype.h/toupper|int toupper(int c);}} || Converts a lowercase letter to a corresponding uppercase letter. || {{C|C89}} |
|- | |- | ||
|} | |} | ||
| − | {{DEFAULTSORT: | + | {{DEFAULTSORT:ctype.h}} |
| − | [[Category: | + | [[Category:ctype.h]] |
| − | |||
Latest revision as of 10:53, 7 January 2015
The <ctype.h> header is part of the standard library of the C programming language that declares several functions useful for classifying and mapping characters.
Some of the functions in this header are local-specific. That is, depending on the locale chosen, some functions behave slightly differently. The minimum locale that must be provided is the "C" locale.
Functions[edit]
All functions in this header take a single argument of type int which should be representable as an unsigned char or be equal to the value of the macro EOF. All other values result in undefined behavior.
Functions in this header falls under two categories:
Character classification functions[edit]
| Function Prototype | Description | Since |
|---|---|---|
| int isalnum(int c); | Checks if c is alphanumeric. | C89 |
| int isalpha(int c); | Checks if c is alphabetic. | C89 |
| int isblank(int c); | Checks if c is blank. | C99 |
| int iscntrl(int c); | Checks if c is a control character. | C89 |
| int isdigit(int c); | Checks if c is a decimal digit. | C89 |
| int isgraph(int c); | Checks if c has a graphical representation. | C89 |
| int islower(int c); | Checks if c is a lowercase letter. | C89 |
| int isprint(int c); | Checks if c is printable. | C89 |
| int ispunct(int c); | Checks if c is a punctuation character. | C89 |
| int isspace(int c); | Checks if c is a white-space character. | C89 |
| int isupper(int c); | Checks if c is an uppercase letter. | C89 |
| int isxdigit(int c); | Checks if c is a hexadecimal digit. | C89 |
Character case mapping functions[edit]
Two functions that deal with character case mapping is provided.
| Function Prototype | Description | Since |
|---|---|---|
| int tolower(int c); | Converts an uppercase letter to a corresponding lowercase letter. | C89 |
| int toupper(int c); | Converts a lowercase letter to a corresponding uppercase letter. | C89 |