ctype.h的C標準庫的頭文件中提供的聲明幾個有用的函數(shù)測試和字符映射。
所有的功能都接受int作為參數(shù),其值必須是EOF或為unsigned char表示。
所有函數(shù)返回的參數(shù)c非零(true),如果滿足條件。否則返回0。
以下是在頭文件ctype.h中定義的函數(shù):
S.N. | 函數(shù)及說明 |
---|---|
1 |
int isalnum(int c) 該函數(shù)檢查傳遞的字符是否是字母數(shù)字。 |
2 |
int isalpha(int c) 該函數(shù)是否傳遞的字符是字母。 |
3 |
int iscntrl(int c) 該函數(shù)是否傳遞的字符是控制字符。 |
4 |
int isdigit(int c) 該函數(shù)是否傳遞的字符是十進制數(shù)字。 |
5 |
int isgraph(int c) 該函數(shù)是否傳遞的字符的圖形表示,使用的語言環(huán)境。 |
6 |
int islower(int c) 該函數(shù)檢查傳遞的字符是否是小寫字母。 |
7 |
int isprint(int c) 該函數(shù)檢查傳遞的字符是否是可打印的。 |
8 |
int ispunct(int c) 該函數(shù)檢查傳遞的字符是否是標點符號。 |
9 |
int isspace(int c) 該函數(shù)檢查傳遞的字符是否是空白。 |
10 |
int isupper(int c) 該函數(shù)檢查傳遞的字符是否是大寫字母。 |
11 |
int isxdigit(int c) 該函數(shù)檢查傳遞的字符是否是十六進制數(shù)字。 |
該庫還包含兩個轉(zhuǎn)換函數(shù),也接受并返回一個“整數(shù)”
S.N. | 函數(shù)及說明 |
---|---|
1 |
int tolower(int c) 這個函數(shù)轉(zhuǎn)換大寫字母為小寫。 |
2 |
int toupper(int c) 這個函數(shù)小寫字母轉(zhuǎn)換為大寫。 |
S.N. | 字符類說明 |
---|---|
1 |
Digits A set of whole numbers { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 } |
2 |
Hexadecimal digits This is the set of { 0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f } |
3 |
Lowercase letters This is a set of { a b c d e f g h i j k l m n o p q r s t u v w x y z } |
4 |
Uppercase letters A set of whole numbers {A B C D E F G H I J K L M N O P Q R S T U V W X Y Z } |
5 |
Letters This is a set of lowercase letters and uppercase letters |
6 |
Alphanumeric characters This is a set of Digits, Lowercase letters and Uppercase letters |
7 |
Punctuation characters This is a set of ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ ] ^ _ ` { | } ~ |
8 |
Graphical characters This is a set of Alphanumeric characters and Punctuation characters. |
9 |
Space characters This is a set of tab, newline, vertical tab, form feed, carriage return, and space. |
10 |
Printable characters This is a set of Alphanumeric characters, Punctuation characters and Space characters. |
11 |
Control characters In ASCII, these characters have octal codes 000 through 037, and 177 (DEL). |
12 |
Blank characters These are space and tab. |
13 |
Alphabetic characters This is a set of Lowercase letters and Uppercase letters. |