c++常用字符串操作函数.doc

1、c+常用字符串操作函数函数名: 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 #include int main(void)char string10;char *str1 = “abcdefghi“;stpcpy(string, str1);printf(“%sn“, 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 #includ

2、e int main(void)char destination25;char *blank = “ “, *c = “C+“, *Borland = “Borland“;strcpy(destination, Borland);strcat(destination, blank);strcat(destination, c);printf(“%sn“, 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 #include int m

3、ain(void)char string15;char *ptr, c = r;strcpy(string, “This is a string“);ptr = strchr(string, c);if (ptr)printf(“The character %c is at position: %dn“, c, ptr-string);elseprintf(“The character was not foundn“);return 0;函数名: strcmp功 能: 串比较用 法: int strcmp(char *str1, char *str2);看 Asic码，str1str2，返回值

4、 0；两串相等，返回 0程序例:#include #include 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 1n“);elseprintf(“buffer 2 is less than buffer 1n“);ptr = strcmp(buf2, buf3);if (ptr 0)printf(“buffer 2 is greater than b

5、uffer 3n“);elseprintf(“buffer 2 is less than buffer 3n“);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 #include int main(void)char *buf1 = “BBB“, *buf2 = “bbb“;int ptr;ptr = strcmpi(buf2, buf1);if (ptr 0)printf(“buffer 2 is

6、greater than buffer 1n“);if (ptr #include int main(void)char string10;char *str1 = “abcdefghi“;strcpy(string, str1);printf(“%sn“, 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 #include #include int main(void)char *string1 = “1234567890“;char

7、 *string2 = “747DC8“;int length;length = strcspn(string1, string2);printf(“Character where strings intersect is at position %dn“, 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 #include #include int main(void)char *dup_str, *string = “abcde“;dup_str = strdup(st

8、ring);printf(“%sn“, 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 #include int main(void)char *buf1 = “BBB“, *buf2 = “bbb“;int ptr;ptr = stricmp(buf2, buf1);if (ptr 0)printf(“buffer 2 is greater than buffer 1n“);if (ptr #include

9、int main(void)char *buffer;buffer = strerror(errno);printf(“Error: %sn“, 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 #include int main(void)char *buf1 = “BBB“, *buf2 = “bbb“;int ptr;ptr = strcmpi(buf2, buf1);if (ptr 0)printf(“buffer 2 is g

10、reater than buffer 1n“);if (ptr #include 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 1n“);elseprintf(“buffer 2 is less than buffer 1n“);ptr = strncmp(buf2,buf3,3);if (ptr 0)printf(“buffer 2

11、is greater than buffer 3n“);elseprintf(“buffer 2 is less than buffer 3n“);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 #include int main(void)char *buf1 = “BBBccc“, *buf2 = “bbbccc“;int ptr;ptr = strncmpi(buf2,buf1,3);if (ptr 0)printf(“b

12、uffer 2 is greater than buffer 1n“);if (ptr #include int main(void)char string10;char *str1 = “abcdefghi“;strncpy(string, str1, 3);string3 = 0;printf(“%sn“, 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 #include int main(void)c

13、har *buf1 = “BBBccc“, *buf2 = “bbbccc“;int ptr;ptr = strnicmp(buf2, buf1, 3);if (ptr 0)printf(“buffer 2 is greater than buffer 1n“);if (ptr #include int main(void)char *string = “abcdefghijklmnopqrstuvwxyz“;char letter = x;printf(“string before strnset: %sn“, string);strnset(string, letter, 13);prin

14、tf(“string after strnset: %sn“, 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 #include int main(void)char *string1 = “abcdefghijklmnopqrstuvwxyz“;char *string2 = “onm“;char *ptr;ptr = strpbrk(string1, string2);if (ptr)printf(“strpbrk found fi

15、rst character: %cn“, *ptr);elseprintf(“strpbrk didnt find character in setn“);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 #include int main(void)char string15;char *ptr, c = r;strcpy(string, “This is a string“);ptr = strrchr(string, c);if (ptr)printf(

16、“The character %c is at position: %dn“, c, ptr-string);elseprintf(“The character was not foundn“);return 0;函数名: strrev功 能: 串倒转用 法: char *strrev(char *str);程序例:#include #include int main(void)char *forward = “string“;printf(“Before strrev(): %sn“, forward);strrev(forward);printf(“After strrev(): %sn“

17、, 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 #include int main(void)char string10 = “123456789“;char symbol = c;printf(“Before strset(): %sn“, string);strset(string, symbol);printf(“After strset(): %sn“, string);return 0;函数名: strspn功 能: 在串中查找

18、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 #include #include int main(void)char *string1 = “1234567890“;char *string2 = “123DC8“;int length;length = strspn(string1, string2);printf(“Character where strings differ is at position %dn“, length);return 0;函数名: strstr功 能: 在串中查找指定字符

19、串的第一次出现用 法: char *strstr(char *str1, char *str2);程序例:#include #include int main(void)char *str1 = “Borland International“, *str2 = “nation“, *ptr;ptr = strstr(str1, str2);printf(“The substring is: %sn“, 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:#in

20、clude #include int main(void)char input80, *endptr;double value;printf(“Enter a floating point number:“);gets(input);value = strtod(input, printf(“The string is %s the number is %lfn“, 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

21、#include int main(void)char input16 = “abc,d“;char *p;p = strtok(input, “,“);if (p) printf(“%sn“, p);p = strtok(NULL, “,“);if (p) printf(“%sn“, 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 #include int main(void)char *string = “87654321“, *endp

22、tr;long lnumber;lnumber = strtol(string, printf(“string = %s long = %ldn“, 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 #include int main(void)char *string = “abcdefghijklmnopqrstuvwxyz“, *ptr;ptr = strupr(string);printf(“%sn“, 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 #include #include char source15 = “rFna koBlrna d“;char target15;int main(void)swab(source, target, strlen(source);printf(“This is target: %sn“, target);return 0;