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\n", 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\n", 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\n", c, ptr-string);
24
25 else
26
27 printf("The character was not found\n");
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\n");
22
23 else
24
25 printf("buffer 2 is less than buffer 1\n");
26
27
28
29 ptr = strcmp(buf2, buf3);
30
31 if (ptr > 0)
32
33 printf("buffer 2 is greater than buffer 3\n");
34
35 else
36
37 printf("buffer 2 is less than buffer 3\n");
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\n");
24
25
26
27 if (ptr < 0)
28
29 printf("buffer 2 is less than buffer 1\n");
30
31
32
33 if (ptr == 0)
34
35 printf("buffer 2 equals buffer 1\n");
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\n", 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\n", 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\n", 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\n");
24
25
26
27 if (ptr < 0)
28
29 printf("buffer 2 is less than buffer 1\n");
30
31
32
33 if (ptr == 0)
34
35 printf("buffer 2 equals buffer 1\n");
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\n", 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\n");
24
25
26
27 if (ptr < 0)
28
29 printf("buffer 2 is less than buffer 1\n");
30
31
32
33 if (ptr == 0)
34
35 printf("buffer 2 equals buffer 1\n");
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\n");
24
25 else
26
27 printf("buffer 2 is less than buffer 1\n");
28
29
30
31 ptr = strncmp(buf2,buf3,3);
32
33 if (ptr > 0)
34
35 printf("buffer 2 is greater than buffer 3\n");
36
37 else
38
39 printf("buffer 2 is less than buffer 3\n");
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\n");
24
25
26
27 if (ptr < 0)
28
29 printf("buffer 2 is less than buffer 1\n");
30
31
32
33 if (ptr == 0)
34
35 printf("buffer 2 equals buffer 1\n");
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\n", 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\n");
24
25
26
27 if (ptr < 0)
28
29 printf("buffer 2 is less than buffer 1\n");
30
31
32
33 if (ptr == 0)
34
35 printf("buffer 2 equals buffer 1\n");
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\n", string);
18
19 strnset(string, letter, 13);
20
21 printf("string after strnset: %s\n", 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\n", *ptr);
26
27 else
28
29 printf("strpbrk didn‘t find character in set\n");
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\n", c, ptr-string);
24
25 else
26
27 printf("The character was not found\n");
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\n", forward);
16
17 strrev(forward);
18
19 printf("After strrev(): %s\n", 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\n", string);
18
19 strset(string, symbol);
20
21 printf("After strset(): %s\n", 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\n", 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\n", 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\n", 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\n", 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\n", 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\n", 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\n", 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\n", target);
22
23 return 0;
24
25 }
来源：https://www.cnblogs.com/wangmengmeng/p/4555295.html