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:
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 }
