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[10];char *str1 = "abcdefghi";stpcpy(string, str1);printf("%s/n", string);return 0;}      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[25];char *blank = " ", *c = "C++", *Borland = "Borland";strcpy(destination, Borland);strcat(destination, blank);strcat(destination, c);printf("%s/n", destination);return 0;}      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[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;}      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 > 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;}      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 > 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;}      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[10];char *str1 = "abcdefghi";strcpy(string, str1);printf("%s/n", string);return 0;}      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 = "1234567890";char *string2 = "747DC8";int length;length = strcspn(string1, string2);printf("Character where strings intersect is at position %d/n", length);return 0;}      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 0;}      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 > 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;}    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 0;}      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 > 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;}      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,buf1,3);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);}    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,buf1,3);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;}    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[10];char *str1 = "abcdefghi";strncpy(string, str1, 3);string[3] = '/0';printf("%s/n", string);return 0;}    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, 3);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;}      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, 13);printf("string after   strnset: %s/n", string);return 0;}    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 0;}      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[15];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 0;}      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 0;}  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[10] = "123456789";char symbol = 'c';printf("Before strset(): %s/n", string);strset(string, symbol);printf("After strset():   %s/n", string);return 0;}      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 = "1234567890";char *string2 = "123DC8";int length;length = strspn(string1, string2);printf("Character where strings differ is at position %d/n", length);return 0;}    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 0;}    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[80], *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 0;}      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[16] = "abc,d";char *p;/* strtok places a NULL terminatorin front of the token, if found */p = strtok(input, ",");if (p) printf("%s/n", p);/* A second call to strtok using a NULLas the first parameter returns a pointerto the character following the token   */p = strtok(NULL, ",");if (p) printf("%s/n", p);return 0;}      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 = "87654321", *endptr;long lnumber;/* strtol converts string to long integer   */lnumber = strtol(string, &endptr, 10);printf("string = %s   long = %ld/n", string, lnumber);return 0;}  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 0;}      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[15] = "rFna koBlrna d";char target[15];int main(void){swab(source, target, strlen(source));printf("This is target: %s/n", target);return 0;}