C Standard Library 简明教程

C Library - <string.h>

string.h 头定义了一个变量类型、一个宏和用于操作字符数组的各种函数。

The string.h header defines one variable type, one macro, and various functions for manipulating arrays of characters.

Library Variables

以下是头 string.h 中定义的变量类型 −

Following is the variable type defined in the header string.h −

Sr.No.

Variable & Description

size_t This is the unsigned integral type and is the result of the sizeof keyword.

C Library string.h Macros

以下是头 string.h 中定义的宏 −

Following is the macro defined in the header string.h −

Sr.No.

Macro & Description

NULL This macro is the value of a null pointer constant.

C Library string.h Functions

以下是头 string.h 中定义的函数 −

Following are the functions defined in the header string.h −

Sr.No.	Function & Description
1	void memchr(const void str, int c, size_t n)Searches for the first occurrence of the character c (an unsigned char) in the first n bytes of the string pointed to, by the argument str.
2	int memcmp(const void str1, const void str2, size_t n)Compares the first n bytes of str1 and str2.
3	void memcpy(void dest, const void *src, size_t n)Copies n characters from src to dest.
4	void memmove(void dest, const void *src, size_t n)Another function to copy n characters from str2 to str1.
5	void memset(void str, int c, size_t n)Copies the character c (an unsigned char) to the first n characters of the string pointed to, by the argument str.
6	char strcat(char dest, const char *src)Appends the string pointed to, by src to the end of the string pointed to by dest.
7	char strncat(char dest, const char *src, size_t n)Appends the string pointed to, by src to the end of the string pointed to, by dest up to n characters long.
8	char strchr(const char str, int c)Searches for the first occurrence of the character c (an unsigned char) in the string pointed to, by the argument str.
9	int strcmp(const char str1, const char str2)Compares the string pointed to, by str1 to the string pointed to by str2.
10	int strncmp(const char str1, const char str2, size_t n)Compares at most the first n bytes of str1 and str2.
11	int strcoll(const char str1, const char str2)Compares string str1 to str2. The result is dependent on the LC_COLLATE setting of the location.
12	char strcpy(char dest, const char *src)Copies the string pointed to, by src to dest.
13	char strncpy(char dest, const char *src, size_t n)Copies up to n characters from the string pointed to, by src to dest.
14	size_t strcspn(const char str1, const char str2)Calculates the length of the initial segment of str1 which consists entirely of characters not in str2.
15	char *strerror(int errnum)Searches an internal array for the error number errnum and returns a pointer to an error message string.
16	size_t strlen(const char *str)Computes the length of the string str up to but not including the terminating null character.
17	char strpbrk(const char str1, const char *str2)Finds the first character in the string str1 that matches any character specified in str2.
18	char strrchr(const char str, int c)Searches for the last occurrence of the character c (an unsigned char) in the string pointed to by the argument str.
19	size_t strspn(const char str1, const char str2)Calculates the length of the initial segment of str1 which consists entirely of characters in str2.
20	char strstr(const char haystack, const char *needle)Finds the first occurrence of the entire string needle (not including the terminating null character) which appears in the string haystack.
21	char strtok(char str, const char *delim)Breaks string str into a series of tokens separated by delim.
22	size_t strxfrm(char *dest, const char src, size_t n)Transforms the first n* characters of the string src into current locale and places them in the string dest.

Sr.No.	Function & Description
1	void memchr(const void str, int c, size_t n)Searches for the first occurrence of the character c (an unsigned char) in the first n bytes of the string pointed to, by the argument str.
2	int memcmp(const void str1, const void str2, size_t n)Compares the first n bytes of str1 and str2.
3	void memcpy(void dest, const void *src, size_t n)Copies n characters from src to dest.
4	void memmove(void dest, const void *src, size_t n)Another function to copy n characters from str2 to str1.
5	void memset(void str, int c, size_t n)Copies the character c (an unsigned char) to the first n characters of the string pointed to, by the argument str.
6	char strcat(char dest, const char *src)Appends the string pointed to, by src to the end of the string pointed to by dest.
7	char strncat(char dest, const char *src, size_t n)Appends the string pointed to, by src to the end of the string pointed to, by dest up to n characters long.
8	char strchr(const char str, int c)Searches for the first occurrence of the character c (an unsigned char) in the string pointed to, by the argument str.
9	int strcmp(const char str1, const char str2)Compares the string pointed to, by str1 to the string pointed to by str2.
10	int strncmp(const char str1, const char str2, size_t n)Compares at most the first n bytes of str1 and str2.
11	int strcoll(const char str1, const char str2)Compares string str1 to str2. The result is dependent on the LC_COLLATE setting of the location.
12	char strcpy(char dest, const char *src)Copies the string pointed to, by src to dest.
13	char strncpy(char dest, const char *src, size_t n)Copies up to n characters from the string pointed to, by src to dest.
14	size_t strcspn(const char str1, const char str2)Calculates the length of the initial segment of str1 which consists entirely of characters not in str2.
15	char *strerror(int errnum)Searches an internal array for the error number errnum and returns a pointer to an error message string.
16	size_t strlen(const char *str)Computes the length of the string str up to but not including the terminating null character.
17	char strpbrk(const char str1, const char *str2)Finds the first character in the string str1 that matches any character specified in str2.
18	char strrchr(const char str, int c)Searches for the last occurrence of the character c (an unsigned char) in the string pointed to by the argument str.
19	size_t strspn(const char str1, const char str2)Calculates the length of the initial segment of str1 which consists entirely of characters in str2.
20	char strstr(const char haystack, const char *needle)Finds the first occurrence of the entire string needle (not including the terminating null character) which appears in the string haystack.
21	char strtok(char str, const char *delim)Breaks string str into a series of tokens separated by delim.
22	size_t strxfrm(char *dest, const char src, size_t n)Transforms the first n* characters of the string src into current locale and places them in the string dest.