C语言的函数!

内财数模协会

<>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 &lt;stdio.h&gt;
#include &lt;string.h&gt; <>int main(void)
{
   char *string = "abcdefghijklmnopqrstuvwxyz";
   char letter = 'x'; <P>   printf("string before strnset: %s\n", string);
   strnset(string, letter, 13);
   printf("string after  strnset: %s\n", string); <P>   return 0;
}
</P>

内财数模协会

<>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 &lt;stdio.h&gt;
#include &lt;string.h&gt; <>int main(void)
{
   char *string1 = "abcdefghijklmnopqrstuvwxyz";
   char *string2 = "onm";
   char *ptr; <P>   ptr = strpbrk(string1, string2); <P>   if (ptr)
      printf("strpbrk found first character: %c\n", *ptr);
   else
      printf("strpbrk didn't find character in set\n"); <P>   return 0;
}
</P>

内财数模协会

<>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 &lt;string.h&gt;
#include &lt;stdio.h&gt; <>int main(void)
{
   char string[15];
   char *ptr, c = 'r'; <P>   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;
}
</P>

内财数模协会

<>函数名: strrev
功  能: 串倒转
用  法: char *strrev(char *str);
程序例: <>#include &lt;string.h&gt;
#include &lt;stdio.h&gt; <>int main(void)
{
   char *forward = "string"; <P>   printf("Before strrev(): %s\n", forward);
   strrev(forward);
   printf("After strrev():  %s\n", forward);
   return 0;
}
  </P>

内财数模协会

<>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 &lt;stdio.h&gt;
#include &lt;string.h&gt; <>int main(void)
{
   char string[10] = "123456789";
   char symbol = 'c'; <P>   printf("Before strset(): %s\n", string);
   strset(string, symbol);
   printf("After strset():  %s\n", string);
   return 0;
}
</P>

内财数模协会

<>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 &lt;stdio.h&gt;
#include &lt;string.h&gt;
#include &lt;alloc.h&gt; <>int main(void)
{
   char *string1 = "1234567890";
   char *string2 = "123DC8";
   int length; <P>   length = strspn(string1, string2);
   printf("Character where strings differ is at position %d\n", length);
   return 0;
}
  
  </P>

内财数模协会

<>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 &lt;stdio.h&gt;
#include &lt;string.h&gt; <>int main(void)
{
   char *str1 = "Borland International", *str2 = "nation", *ptr; <P>   ptr = strstr(str1, str2);
   printf("The substring is: %s\n", ptr);
   return 0;
}
</P>

内财数模协会

<>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 &lt;stdio.h&gt;
#include &lt;stdlib.h&gt; <>int main(void)
{
   char input[80], *endptr;
   double value; <P>   printf("Enter a floating point number:");
   gets(input);
   value = strtod(input, &amp;endptr);
   printf("The string is %s the number is %lf\n", input, value);
   return 0;
}
</P>

内财数模协会

<>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 &lt;string.h&gt;
#include &lt;stdio.h&gt; <>int main(void)
{
   char input[16] = "abc,d";
   char *p; <P>   /* strtok places a NULL terminator
   in front of the token, if found */
   p = strtok(input, ",");
   if (p)   printf("%s\n", p); <P>   /* A second call to strtok using a NULL
   as the first parameter returns a pointer
   to the character following the token  */
   p = strtok(NULL, ",");
   if (p)   printf("%s\n", p);
   return 0;
}
  
  
</P>

内财数模协会

<>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 &lt;stdlib.h&gt;
#include &lt;stdio.h&gt; <>int main(void)
{
   char *string = "87654321", *endptr;
   long lnumber; <P>   /* strtol converts string to long integer  */
   lnumber = strtol(string, &amp;endptr, 10);
   printf("string = %s  long = %ld\n", string, lnumber); <P>   return 0;
}
  </P>