strstr函数

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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: 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[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 <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: 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;

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 <stdlib.h>
#include <stdio.h>

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 <stdio.h>
#include <string.h>

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 <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; 原型：extern char *strstr(char *haystack, char *needle); 所在头文件：#include <string.h> 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：

Download:strstr_sample.c