strstr函数头文件_strstr函数[通俗易懂]

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

#include

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: 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 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

#include

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

#include

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

#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 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

#include

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

#include

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

#include

#include

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

#include

#include

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

#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 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

#include

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

#include

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

#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 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

#include

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

#include

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

#include

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

#include

int main(void)

{

char string[50] =

“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

#include

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

#include

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

#include

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

#include

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

#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 %d\n”, length);

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

#include

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

#include

int main(void)

{

char input[16] =

“abc,d”;

char *p;

p = strtok(input, “,”);

if

(p) printf(“%s\n”, p);

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

#include

int main(void)

{

char *string = “87654321”,

*endptr;

long lnumber;

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

#include

int main(void)

{

char *string =

“abcdefghijklmnopqrstuvwxyz”, *ptr;

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

#include

#include

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;

原型：extern char *strstr(char *haystack, char *needle);

所在头文件：#include

功能：从字符串haystack中寻找needle第一次出现的位置(不比较结束符NULL)。

说明：返回指向第一次出现needle位置的指针，如果没找到则返回NULL。

具体使用例子：

#include

#include

int main(int argc,char **argv)

{

char *haystack=”aaa||a||bbb||c||ee||”;

char *needle=”||”;

char*

buf = strstr(

haystack, needle);

while( buf

!= NULL )

{

buf[0]=’\0′;

printf( “%s\n

“, haystack);

haystack = buf

+ strlen(needle);

buf = strstr(

haystack, needle);

}

return 0;

}