說起字元串函數,我想大家都不陌生。字元串函數對二進制資料、字元串和表達式執行不同的運算。下面總結了C語言中的字元串函數。
1、函數名: stpcpy
功 能: 拷貝一個字元串到另一個
用 法:
- char *stpcpy(char *destin, char *source);
程式例:
- #include <stdio.h>
- #include <string.h>
- int main(void)
- {
- char string[10];
- char *str1 = "abcdefghi";
- stpcpy(string, str1);
- printf("%s\n", string);
- return 0;
- }
2、函數名: strcat
功 能: 字元串拼接函數
用 法:
- char *strcat(char *destin, char *source);
程式例:
- #include <string.h>
- #include <stdio.h>
- int main(void)
- {
- char destination[25];
- char *blank = " ", *c = "C++", *Borland = "Borland";
- strcpy(destination, Borland);
- strcat(destination, blank);
- strcat(destination, c);
- printf("%s\n", destination);
- return 0;
- }
3、函數名: strchr
功 能: 在一個串中查找給定字元的第一個比對之處\
用 法:
- char *strchr(char *str, char c);
程式例:
- #include <string.h>
- #include <stdio.h>
- int main(void)
- {
- char string[15];
- 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 0;
- }
4、函數名: strcmp
功 能: 串比較
用 法:
- int strcmp(char *str1, char *str2);
看Asic碼,str1>str2,傳回值 > 0;兩串相等,傳回0
程式例:
- #include <string.h>
- #include <stdio.h>
- int main(void)
- {
- char *buf1 = "aaa", *buf2 = "bbb", *buf3 = "ccc";
- int ptr;
- ptr = strcmp(buf2, buf1);
- if (ptr > 0)
- 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 > 0)
- printf("buffer 2 is greater than buffer 3\n");
- else
- printf("buffer 2 is less than buffer 3\n");
- return 0;
- }
5、函數名: strncmpi
功 能: 将一個串中的一部分與另一個串比較, 不管大小寫
用 法:
- int strncmpi(char *str1, char *str2, unsigned maxlen);
程式例:
- #include <string.h>
- #include <stdio.h>
- int main(void)
- {
- char *buf1 = "BBB", *buf2 = "bbb";
- int ptr;
- ptr = strcmpi(buf2, buf1);
- if (ptr > 0)
- printf("buffer 2 is greater than buffer 1\n");
- if (ptr < 0)
- printf("buffer 2 is less than buffer 1\n");
- if (ptr == 0)
- printf("buffer 2 equals buffer 1\n");
- return 0;
- }
6、函數名: strcpy
功 能: 串拷貝
用 法:
- char *strcpy(char *str1, char *str2);
程式例:
- #include <stdio.h>
- #include <string.h>
- int main(void)
- {
- char string[10];
- char *str1 = "abcdefghi";
- strcpy(string, str1);
- printf("%s\n", string);
- return 0;
- }
7、函數名: strcspn
功 能: 在串中查找第一個給定字元集内容的段
用 法:
- int strcspn(char *str1, char *str2);
程式例:
- #include <stdio.h>
- #include <string.h>
- #include <alloc.h>
- int main(void)
- {
- char *string1 = "1234567890";
- char *string2 = "747DC8";
- int length;
- length = strcspn(string1, string2);
- printf("Character where strings intersect is at position %d\n", length);
- return 0;
- }
8、函數名: strdup
功 能: 将串拷貝到建立的位置處
用 法:
- char *strdup(char *str);
程式例:
- #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 0;
- }
9、函數名: stricmp
功 能: 以大小寫不敏感方式比較兩個串
用 法:
- int stricmp(char *str1, char *str2);
程式例:
- #include <string.h>
- #include <stdio.h>
- int main(void)
- {
- char *buf1 = "BBB", *buf2 = "bbb";
- int ptr;
- ptr = stricmp(buf2, buf1);
- if (ptr > 0)
- printf("buffer 2 is greater than buffer 1\n");
- if (ptr < 0)
- printf("buffer 2 is less than buffer 1\n");
- if (ptr == 0)
- printf("buffer 2 equals buffer 1\n");
- return 0;
- }
10、函數名: strerror
功 能: 傳回指向錯誤資訊字元串的指針
用 法:
- char *strerror(int errnum);
程式例:
- #include <stdio.h>
- #include <errno.h>
- int main(void)
- {
- char *buffer;
- buffer = strerror(errno);
- printf("Error: %s\n", buffer);
- return 0;
- }
11、函數名: strcmpi
功 能: 将一個串與另一個比較, 不管大小寫
用 法:
- int strcmpi(char *str1, char *str2);
程式例:
- #include <string.h>
- #include <stdio.h>
- int main(void)
- {
- char *buf1 = "BBB", *buf2 = "bbb";
- int ptr;
- ptr = strcmpi(buf2, buf1);
- if (ptr > 0)
- printf("buffer 2 is greater than buffer 1\n");
- if (ptr < 0)
- printf("buffer 2 is less than buffer 1\n");
- if (ptr == 0)
- printf("buffer 2 equals buffer 1\n");
- return 0;
- }
12、函數名: strncmp
功 能: 串比較
用 法:
- int strncmp(char *str1, char *str2, int maxlen);
程式例:
- #include <string.h>
- #include <stdio.h>
- int main(void)
- {
- char *buf1 = "aaabbb", *buf2 = "bbbccc", *buf3 = "ccc";
- int ptr;
- ptr = strncmp(buf2,buf1,3);
- if (ptr > 0)
- printf("buffer 2 is greater than buffer 1\n");
- else
- printf("buffer 2 is less than buffer 1\n");
- ptr = strncmp(buf2,buf3,3);
- if (ptr > 0)
- printf("buffer 2 is greater than buffer 3\n");
- else
- printf("buffer 2 is less than buffer 3\n");
- return(0);
- }