C语言字符串函数大全

C语言字符串函数大全

函数名: stpcpy

功 能: 拷贝一个字符串到另一个

用 法: char *stpcpy(char *destin, char *source);

程序例:

 #include <stdio.h>

 #include <string.h>

 int main(void)

 {

     char string[];

     char *str1 = "abcdefghi";

     stpcpy(string, str1);

     printf("%s\n", string);

     return ;

 }

函数名: strcat

功 能: 字符串拼接函数

用 法: char *strcat(char *destin, char *source);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char destination[];

     char *blank = " ", *c = "C++", *Borland = "Borland";

     strcpy(destination, Borland);

     strcat(destination, blank);

     strcat(destination, c);

     printf("%s\n", destination);

     return ;

 }

函数名: strchr

功 能: 在一个串中查找给定字符的第一个匹配之处

用 法: char *strchr(char *str, char c);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char string[];

     char *ptr, c = ‘r‘;

     strcpy(string, "This is a string");

     ptr = strchr(string, c);

     if (ptr)

     printf("The character %c is at position: %d\n", c, ptr-string);

     else

     printf("The character was not found\n");

     return ;

 }

函数名: strcmp

功 能: 串比较

用 法: int strcmp(char *str1, char *str2);

看Asic码，str1>str2，返回值 > 0；两串相等，返回0

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char *buf1 = "aaa", *buf2 = "bbb", *buf3 = "ccc";

     int ptr;

     ptr = strcmp(buf2, buf1);

     if (ptr > )

     printf("buffer 2 is greater than buffer 1\n");

     else

     printf("buffer 2 is less than buffer 1\n");

     ptr = strcmp(buf2, buf3);

     if (ptr > )

     printf("buffer 2 is greater than buffer 3\n");

     else

     printf("buffer 2 is less than buffer 3\n");

     return ;

 }

函数名: strncmpi

功 能: 将一个串中的一部分与另一个串比较, 不管大小写

用 法: int strncmpi(char *str1, char *str2, unsigned maxlen);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char *buf1 = "BBB", *buf2 = "bbb";

     int ptr;

     ptr = strcmpi(buf2, buf1);

     if (ptr > )

     printf("buffer 2 is greater than buffer 1\n");

     if (ptr < )

     printf("buffer 2 is less than buffer 1\n");

     if (ptr == )

     printf("buffer 2 equals buffer 1\n");

     return ;

 }

函数名: strcpy

功 能: 串拷贝

用 法: char *strcpy(char *str1, char *str2);

程序例:

 #include <stdio.h>

 #include <string.h>

 int main(void)

 {

     char string[];

     char *str1 = "abcdefghi";

     strcpy(string, str1);

     printf("%s\n", string);

     return ;

 }

函数名: strcspn

功 能: 在串中查找第一个给定字符集内容的段

用 法: int strcspn(char *str1, char *str2);

程序例:

 #include <stdio.h>

 #include <string.h>

 #include <alloc.h>

 int main(void)

 {

     char *string1 = "";

     char *string2 = "747DC8";

     int length;

     length = strcspn(string1, string2);

     printf("Character where strings intersect is at position %d\n", length);

     return ;

 }

函数名: strdup

功 能: 将串拷贝到新建的位置处

用 法: char *strdup(char *str);

程序例:

 #include <stdio.h>

 #include <string.h>

 #include <alloc.h>

 int main(void)

 {

     char *dup_str, *string = "abcde";

     dup_str = strdup(string);

     printf("%s\n", dup_str);

     free(dup_str);

     return ;

 }

函数名: stricmp

功 能: 以大小写不敏感方式比较两个串

用 法: int stricmp(char *str1, char *str2);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char *buf1 = "BBB", *buf2 = "bbb";

     int ptr;

     ptr = stricmp(buf2, buf1);

     if (ptr > )

     printf("buffer 2 is greater than buffer 1\n");

     if (ptr < )

     printf("buffer 2 is less than buffer 1\n");

     if (ptr == )

     printf("buffer 2 equals buffer 1\n");

     return ;

 }

函数名: strerror

功 能: 返回指向错误信息字符串的指针

用 法: char *strerror(int errnum);

程序例:

 #include <stdio.h>

 #include <errno.h>

 int main(void)

 {

     char *buffer;

     buffer = strerror(errno);

     printf("Error: %s\n", buffer);

     return ;

 }

函数名: strcmpi

功 能: 将一个串与另一个比较, 不管大小写

用 法: int strcmpi(char *str1, char *str2);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char *buf1 = "BBB", *buf2 = "bbb";

     int ptr;

     ptr = strcmpi(buf2, buf1);

     if (ptr > )

     printf("buffer 2 is greater than buffer 1\n");

     if (ptr < )

     printf("buffer 2 is less than buffer 1\n");

     if (ptr == )

     printf("buffer 2 equals buffer 1\n");

     return ;

 }

函数名: strncmp

功 能: 串比较

用 法: int strncmp(char *str1, char *str2, int maxlen);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char *buf1 = "aaabbb", *buf2 = "bbbccc", *buf3 = "ccc";

     int ptr;

     ptr = strncmp(buf2,buf1,);

     if (ptr > )

     printf("buffer 2 is greater than buffer 1\n");

     else

     printf("buffer 2 is less than buffer 1\n");

     ptr = strncmp(buf2,buf3,);

     if (ptr > )

     printf("buffer 2 is greater than buffer 3\n");

     else

     printf("buffer 2 is less than buffer 3\n");

     return();

 }

函数名: strncmpi

功 能: 把串中的一部分与另一串中的一部分比较, 不管大小写

用 法: int strncmpi(char *str1, char *str2);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char *buf1 = "BBBccc", *buf2 = "bbbccc";

     int ptr;

     ptr = strncmpi(buf2,buf1,);

     if (ptr > )

     printf("buffer 2 is greater than buffer 1\n");

     if (ptr < )

     printf("buffer 2 is less than buffer 1\n");

     if (ptr == )

     printf("buffer 2 equals buffer 1\n");

     return ;

 }

函数名: strncpy

功 能: 串拷贝

用 法: char *strncpy(char *destin, char *source, int maxlen);

程序例:

 #include <stdio.h>

 #include <string.h>

 int main(void)

 {

     char string[];

     char *str1 = "abcdefghi";

     strncpy(string, str1, );

     string[] = ‘\‘;

     printf("%s\n", string);

     return ;

 }

函数名: strnicmp

功 能: 不注重大小写地比较两个串

用 法: int strnicmp(char *str1, char *str2, unsigned maxlen);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char *buf1 = "BBBccc", *buf2 = "bbbccc";

     int ptr;

     ptr = strnicmp(buf2, buf1, );

     if (ptr > )

     printf("buffer 2 is greater than buffer 1\n");

     if (ptr < )

     printf("buffer 2 is less than buffer 1\n");

     if (ptr == )

     printf("buffer 2 equals buffer 1\n");

     return ;

 }

函数名: strnset

功 能: 将一个串中的所有字符都设为指定字符

用 法: char *strnset(char *str, char ch, unsigned n);

程序例:

 #include <stdio.h>

 #include <string.h>

 int main(void)

 {

     char *string = "abcdefghijklmnopqrstuvwxyz";

     char letter = ‘x‘;

     printf("string before strnset: %s\n", string);

     strnset(string, letter, );

     printf("string after  strnset: %s\n", string);

     return ;

 }

函数名: strpbrk

功 能: 在串中查找给定字符集中的字符

用 法: char *strpbrk(char *str1, char *str2);

程序例:

 #include <stdio.h>

 #include <string.h>

 int main(void)

 {

     char *string1 = "abcdefghijklmnopqrstuvwxyz";

     char *string2 = "onm";

     char *ptr;

     ptr = strpbrk(string1, string2);

     if (ptr)

     printf("strpbrk found first character: %c\n", *ptr);

     else

     printf("strpbrk didn‘t find character in set\n");

     return ;

 }

函数名: strrchr

功 能: 在串中查找指定字符的最后一个出现

用 法: char *strrchr(char *str, char c);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char string[];

     char *ptr, c = ‘r‘;

     strcpy(string, "This is a string");

     ptr = strrchr(string, c);

     if (ptr)

     printf("The character %c is at position: %d\n", c, ptr-string);

     else

     printf("The character was not found\n");

     return ;

 }

函数名: strrev

功 能: 串倒转

用 法: char *strrev(char *str);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char *forward = "string";

     printf("Before strrev(): %s\n", forward);

     strrev(forward);

     printf("After strrev():  %s\n", forward);

     return ;

 }

函数名: strset

功 能: 将一个串中的所有字符都设为指定字符

用 法: char *strset(char *str, char c);

程序例:

 #include <stdio.h>

 #include <string.h>

 int main(void)

 {

     char string[] = "";

     char symbol = ‘c‘;

     printf("Before strset(): %s\n", string);

     strset(string, symbol);

     printf("After strset():  %s\n", string);

     return ;

 }

 函数名: strspn

 功 能: 在串中查找指定字符集的子集的第一次出现

 用 法: int strspn(char *str1, char *str2);

 程序例:

 #include <stdio.h>

 #include <string.h>

 #include <alloc.h>

 int main(void)

 {

     char *string1 = "";

     char *string2 = "123DC8";

     int length;

     length = strspn(string1, string2);

     printf("Character where strings differ is at position %d\n", length);

     return ;

 }

函数名: strstr

功 能: 在串中查找指定字符串的第一次出现

用 法: char *strstr(char *str1, char *str2);

程序例:

 #include <stdio.h>

 #include <string.h>

 int main(void)

 {

     char *str1 = "Borland International", *str2 = "nation", *ptr;

     ptr = strstr(str1, str2);

     printf("The substring is: %s\n", ptr);

     return ;

 }

函数名: strtod

功 能: 将字符串转换为double型值

用 法: double strtod(char *str, char **endptr);

程序例:

 #include <stdio.h>

 #include <stdlib.h>

 int main(void)

 {

     char input[], *endptr;

     double value;

     printf("Enter a floating point number:");

     gets(input);

     value = strtod(input, &endptr);

     printf("The string is %s the number is %lf\n", input, value);

     return ;

 }

函数名: strtok

功 能: 查找由在第二个串中指定的分界符分隔开的单词

用 法: char *strtok(char *str1, char *str2);

程序例:

 #include <string.h>

 #include <stdio.h>

 int main(void)

 {

     char input[] = "abc,d";

     char *p;

     /* strtok places a NULL terminator

      in front of the token, if found */

     p = strtok(input, ",");

     if (p) printf("%s\n", p);

     /* A second call to strtok using a NULL

      as the first parameter returns a pointer

      to the character following the token  */

     p = strtok(NULL, ",");

     if (p) printf("%s\n", p);

     return ;

 }

函数名: strtol

功 能: 将串转换为长整数

用 法: long strtol(char *str, char **endptr, int base);

程序例:

 #include <stdlib.h>

 #include <stdio.h>

 int main(void)

 {

     char *string = "", *endptr;

     long lnumber;

     /* strtol converts string to long integer  */

     lnumber = strtol(string, &endptr, );

     printf("string = %s  long = %ld\n", string, lnumber);

     return ;

 }

函数名: strupr

功 能: 将串中的小写字母转换为大写字母

用 法: char *strupr(char *str);

程序例:

 #include <stdio.h>

 #include <string.h>

 int main(void)

 {

     char *string = "abcdefghijklmnopqrstuvwxyz", *ptr;

     /* converts string to upper case characters */

     ptr = strupr(string);

     printf("%s\n", ptr);

     return ;

 }

函数名: swab

功 能: 交换字节

用 法: void swab (char *from, char *to, int nbytes);

程序例:

 #include <stdlib.h>

 #include <stdio.h>

 #include <string.h>

 char source[] = "rFna koBlrna d";

 char target[];

 int main(void)

 {

     swab(source, target, strlen(source));

     printf("This is target: %s\n", target);

     return ;

 }