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:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char string[10];
12 
13     char *str1 = "abcdefghi";
14 
15  
16 
17     stpcpy(string, str1);
18 
19     printf("%s
", string);
20 
21     return 0;
22 
23 }

函数名: strcat

功能: 字符串拼接函数

用法: char *strcat(char *destin, char *source);

程序例:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char destination[25];
12 
13     char *blank = " ", *c = "C++", *Borland = "Borland";
14 
15  
16 
17     strcpy(destination, Borland);
18 
19     strcat(destination, blank);
20 
21     strcat(destination, c);
22 
23  
24 
25     printf("%s
", destination);
26 
27     return 0;
28 
29 }

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char string[15];
12 
13     char *ptr, c = ‘r‘;
14 
15  
16 
17     strcpy(string, "This is a string");
18 
19     ptr = strchr(string, c);
20 
21     if (ptr)
22 
23     printf("The character %c is at position: %d
", c, ptr-string);
24 
25     else
26 
27     printf("The character was not found
");
28 
29     return 0;
30 
31 }

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *buf1 = "aaa", *buf2 = "bbb", *buf3 = "ccc";
12 
13     int ptr;
14 
15  
16 
17     ptr = strcmp(buf2, buf1);
18 
19     if (ptr > 0)
20 
21     printf("buffer 2 is greater than buffer 1
");
22 
23     else
24 
25     printf("buffer 2 is less than buffer 1
");
26 
27  
28 
29     ptr = strcmp(buf2, buf3);
30 
31     if (ptr > 0)
32 
33     printf("buffer 2 is greater than buffer 3
");
34 
35     else
36 
37     printf("buffer 2 is less than buffer 3
");
38 
39  
40 
41     return 0;
42 
43 }
44 
45

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *buf1 = "BBB", *buf2 = "bbb";
12 
13     int ptr;
14 
15  
16 
17     ptr = strcmpi(buf2, buf1);
18 
19  
20 
21     if (ptr > 0)
22 
23     printf("buffer 2 is greater than buffer 1
");
24 
25  
26 
27     if (ptr < 0)
28 
29     printf("buffer 2 is less than buffer 1
");
30 
31  
32 
33     if (ptr == 0)
34 
35     printf("buffer 2 equals buffer 1
");
36 
37  
38 
39     return 0;
40 
41 }

函数名: strcpy

功能: 串拷贝

用法: char *strcpy(char *str1, char *str2);

程序例:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char string[10];
12 
13     char *str1 = "abcdefghi";
14 
15  
16 
17     strcpy(string, str1);
18 
19     printf("%s
", string);
20 
21     return 0;
22 
23 }

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:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5 #include <alloc.h>
 6 
 7  
 8 
 9 int main(void)
10 
11 {
12 
13     char *string1 = "1234567890";
14 
15     char *string2 = "747DC8";
16 
17     int length;
18 
19  
20 
21     length = strcspn(string1, string2);
22 
23     printf("Character where strings intersect is at position %d
", length);
24 
25  
26 
27     return 0;
28 
29 }

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:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5 #include <alloc.h>
 6 
 7  
 8 
 9 int main(void)
10 
11 {
12 
13     char *dup_str, *string = "abcde";
14 
15  
16 
17     dup_str = strdup(string);
18 
19     printf("%s
", dup_str);
20 
21     free(dup_str);
22 
23  
24 
25     return 0;
26 
27 }

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *buf1 = "BBB", *buf2 = "bbb";
12 
13     int ptr;
14 
15  
16 
17     ptr = stricmp(buf2, buf1);
18 
19  
20 
21     if (ptr > 0)
22 
23     printf("buffer 2 is greater than buffer 1
");
24 
25  
26 
27     if (ptr < 0)
28 
29     printf("buffer 2 is less than buffer 1
");
30 
31  
32 
33     if (ptr == 0)
34 
35     printf("buffer 2 equals buffer 1
");
36 
37  
38 
39     return 0;
40 
41 }

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:

 1 #include <stdio.h>
 2 
 3 #include <errno.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *buffer;
12 
13     buffer = strerror(errno);
14 
15     printf("Error: %s
", buffer);
16 
17     return 0;
18 
19 }

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *buf1 = "BBB", *buf2 = "bbb";
12 
13     int ptr;
14 
15  
16 
17     ptr = strcmpi(buf2, buf1);
18 
19  
20 
21     if (ptr > 0)
22 
23     printf("buffer 2 is greater than buffer 1
");
24 
25  
26 
27     if (ptr < 0)
28 
29     printf("buffer 2 is less than buffer 1
");
30 
31  
32 
33     if (ptr == 0)
34 
35     printf("buffer 2 equals buffer 1
");
36 
37  
38 
39     return 0;
40 
41 }

函数名: strncmp

功能: 串比较

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

程序例:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9  
10 
11 {
12 
13     char *buf1 = "aaabbb", *buf2 = "bbbccc", *buf3 = "ccc";
14 
15     int ptr;
16 
17  
18 
19     ptr = strncmp(buf2,buf1,3);
20 
21     if (ptr > 0)
22 
23     printf("buffer 2 is greater than buffer 1
");
24 
25     else
26 
27     printf("buffer 2 is less than buffer 1
");
28 
29  
30 
31     ptr = strncmp(buf2,buf3,3);
32 
33     if (ptr > 0)
34 
35     printf("buffer 2 is greater than buffer 3
");
36 
37     else
38 
39     printf("buffer 2 is less than buffer 3
");
40 
41  
42 
43     return(0);
44 
45 }

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *buf1 = "BBBccc", *buf2 = "bbbccc";
12 
13     int ptr;
14 
15  
16 
17     ptr = strncmpi(buf2,buf1,3);
18 
19  
20 
21     if (ptr > 0)
22 
23     printf("buffer 2 is greater than buffer 1
");
24 
25  
26 
27     if (ptr < 0)
28 
29     printf("buffer 2 is less than buffer 1
");
30 
31  
32 
33     if (ptr == 0)
34 
35     printf("buffer 2 equals buffer 1
");
36 
37  
38 
39     return 0;
40 
41 }

函数名: strncpy

功能: 串拷贝

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

程序例:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char string[10];
12 
13     char *str1 = "abcdefghi";
14 
15  
16 
17     strncpy(string, str1, 3);
18 
19     string[3] = ‘0‘;
20 
21     printf("%s
", string);
22 
23     return 0;
24 
25 }

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *buf1 = "BBBccc", *buf2 = "bbbccc";
12 
13     int ptr;
14 
15  
16 
17     ptr = strnicmp(buf2, buf1, 3);
18 
19  
20 
21     if (ptr > 0)
22 
23     printf("buffer 2 is greater than buffer 1
");
24 
25  
26 
27     if (ptr < 0)
28 
29     printf("buffer 2 is less than buffer 1
");
30 
31  
32 
33     if (ptr == 0)
34 
35     printf("buffer 2 equals buffer 1
");
36 
37  
38 
39     return 0;
40 
41 }

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:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *string = "abcdefghijklmnopqrstuvwxyz";
12 
13     char letter = ‘x‘;
14 
15  
16 
17     printf("string before strnset: %s
", string);
18 
19     strnset(string, letter, 13);
20 
21     printf("string after  strnset: %s
", string);
22 
23  
24 
25     return 0;
26 
27 }

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:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *string1 = "abcdefghijklmnopqrstuvwxyz";
12 
13     char *string2 = "onm";
14 
15     char *ptr;
16 
17  
18 
19     ptr = strpbrk(string1, string2);
20 
21  
22 
23     if (ptr)
24 
25     printf("strpbrk found first character: %c
", *ptr);
26 
27     else
28 
29     printf("strpbrk didn‘t find character in set
");
30 
31  
32 
33     return 0;
34 
35 }

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char string[15];
12 
13     char *ptr, c = ‘r‘;
14 
15  
16 
17     strcpy(string, "This is a string");
18 
19     ptr = strrchr(string, c);
20 
21     if (ptr)
22 
23     printf("The character %c is at position: %d
", c, ptr-string);
24 
25     else
26 
27     printf("The character was not found
");
28 
29     return 0;
30 
31 }

函数名: strrev

功能: 串倒转

用法: char *strrev(char *str);

程序例:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *forward = "string";
12 
13  
14 
15     printf("Before strrev(): %s
", forward);
16 
17     strrev(forward);
18 
19     printf("After strrev():  %s
", forward);
20 
21     return 0;
22 
23 }

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:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char string[10] = "123456789";
12 
13     char symbol = ‘c‘;
14 
15  
16 
17     printf("Before strset(): %s
", string);
18 
19     strset(string, symbol);
20 
21     printf("After strset():  %s
", string);
22 
23     return 0;
24 
25 }
26 
27  
28 
29 函数名: strspn
30 
31 功 能: 在串中查找指定字符集的子集的第一次出现
32 
33 用 法: int strspn(char *str1, char *str2);
34 
35 程序例:
36 
37  
38 
39 #include <stdio.h>
40 
41 #include <string.h>
42 
43 #include <alloc.h>
44 
45  
46 
47 int main(void)
48 
49 {
50 
51     char *string1 = "1234567890";
52 
53     char *string2 = "123DC8";
54 
55     int length;
56 
57  
58 
59     length = strspn(string1, string2);
60 
61     printf("Character where strings differ is at position %d
", length);
62 
63     return 0;
64 
65 }

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:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *str1 = "Borland International", *str2 = "nation", *ptr;
12 
13  
14 
15     ptr = strstr(str1, str2);
16 
17     printf("The substring is: %s
", ptr);
18 
19     return 0;
20 
21 }

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:

 1 #include <stdio.h>
 2 
 3 #include <stdlib.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char input[80], *endptr;
12 
13     double value;
14 
15  
16 
17     printf("Enter a floating point number:");
18 
19     gets(input);
20 
21     value = strtod(input, &endptr);
22 
23     printf("The string is %s the number is %lf
", input, value);
24 
25     return 0;
26 
27 }

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:

 1 #include <string.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char input[16] = "abc,d";
12 
13     char *p;
14 
15  
16 
17     /* strtok places a NULL terminator
18 
19      in front of the token, if found */
20 
21     p = strtok(input, ",");
22 
23     if (p) printf("%s
", p);
24 
25  
26 
27     /* A second call to strtok using a NULL
28 
29      as the first parameter returns a pointer
30 
31      to the character following the token  */
32 
33     p = strtok(NULL, ",");
34 
35     if (p) printf("%s
", p);
36 
37     return 0;
38 
39 }

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:

 1 #include <stdlib.h>
 2 
 3 #include <stdio.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *string = "87654321", *endptr;
12 
13     long lnumber;
14 
15  
16 
17     /* strtol converts string to long integer  */
18 
19     lnumber = strtol(string, &endptr, 10);
20 
21     printf("string = %s  long = %ld
", string, lnumber);
22 
23  
24 
25     return 0;
26 
27 }

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:

 1 #include <stdio.h>
 2 
 3 #include <string.h>
 4 
 5  
 6 
 7 int main(void)
 8 
 9 {
10 
11     char *string = "abcdefghijklmnopqrstuvwxyz", *ptr;
12 
13  
14 
15     /* converts string to upper case characters */
16 
17     ptr = strupr(string);
18 
19     printf("%s
", ptr);
20 
21     return 0;
22 
23 }

函数名: swab

功能: 交换字节

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

程序例:

 1 #include <stdlib.h>
 2 
 3 #include <stdio.h>
 4 
 5 #include <string.h>
 6 
 7  
 8 
 9 char source[15] = "rFna koBlrna d";
10 
11 char target[15];
12 
13  
14 
15 int main(void)
16 
17 {
18 
19     swab(source, target, strlen(source));
20 
21     printf("This is target: %s
", target);
22 
23     return 0;
24 
25 }