常用字符串处理函数

常用字符串处理函数(string.h)
1、strlen：求字符串长度
size_t strlen(const char *str);
2、strcpy/strncpy：字符串复制
char *strcpy(char *strDestination, const char *strSource);
char *strncpy(char *strDest, const char *strSource, size_t count);
3、strcat/strncat：字符串连接
char *strcat(char *strDestination, const char *strSource);
char *strncat( char *strDest, const char *strSource, size_t count);
4、strcmp/strncmp：字符串比较
int strcmp(const char *string1, const char *string2);
int strncmp(const char *string1, const char *string2, size_t count);
5、strstr：查找子串
char *strstr(const char *str, const char *strSearch);
Parameters
str
Null-terminated string to search.
strSearch
Null-terminated string to search for.
Return Value
Returns a pointer to the first occurrence of strSearch in str, or NULL if strSearch does not appear in str. If strSearch points to a string of zero length, the function returns str.
6、strpbrk：查找字符串strCharSet中的任意字符在字符串str中首次出现的位置char *strpbrk(const char * str, const char *strCharSet);
Parameters
str
Null-terminated, searched string.
strCharSet
Null-terminated character set.
Return Value
Returns a pointer to the first occurrence of any character from strCharSet in str, or a NULL pointer if the two string arguments have no characters in common.
7、struper：把字符串中的所有小写字母改为大写字母
char *_strupr(char *str);
Parameters
str
String to capitalize.
Return Value
Returns a pointer to the altered string. Because the modification is done in place, the pointer returned is the same as the pointer passed as the input argument. No return value is reserved to indicate an error.
与字符串有关的标准输入/输出函数(stdio.h)
1、sprintf：输出到字符串
int sprintf(char *buffer,const char *format [,argument] ...);
Parameters
buffer
Storage location for output
format
Format-control string
argument
Optional arguments
Return Value
The number of characters written, or –1 if an error occurred. If buffer or format is a null pointer, the invalid parameter handler is invoked, as described in Parameter Validation. If execution is allowed to continue, these functions return -1 and set errno to EINV AL.
sprintf returns the number of bytes stored in buffer, not counting the terminating null character.
2、sscanf：从字符串中输入
int sscanf(const char *buffer, const char *format [,argument ] ...);
Parameters
buffer
Stored data
format
Format-control string.
argument
Optional arguments
Return Value
Each of these functions returns the number of fields successfully converted and assigned; the return value does not include fields that were read but not assigned. A return value of 0 indicates that no fields were assigned. The return value is EOF for an error or if the end of the string is reached before the first conversion.
If buffer or format is a NULL pointer, the invalid parameter handler is invoked, as described in Parameter Validation. If execution is allowed to continue, these functions return -1 and set errno to EINV AL。