C/C++

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/*
 * Get next token from string *stringp, where tokens are possibly-empty
 * strings separated by characters from delim.
 *
 * Writes NULs into the string at *stringp to end tokens.
 * delim need not remain constant from call to call.
 * On return, *stringp points past the last NUL written (if there might
 * be further tokens), or is NULL (if there are definitely no more tokens).
 *
 * If *stringp is NULL, strsep returns NULL.
 */
char *
strsep(stringp, delim)
    char **stringp;
    const char *delim;
{
    char *s;
    const char *spanp;
    int c, sc;
    char *tok;

    if ((s = *stringp) == NULL)
        return (NULL);
    for (tok = s;;) {
        c = *s++;
        spanp = delim;
        do {
            if ((sc = *spanp++) == c) {
                if (c == 0)
                    s = NULL;
                else
                    s[-1] = 0;
                *stringp = s;
                return (tok);
            }
        } while (sc != 0);
    }
    /* NOTREACHED */
}

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#include "string.h"
#include "stdlib.h"
#include "stdio.h"

int main ()
{
  char str[] = "This is a sample string";
  char key[] = "aeiou";
  char * pch;
  printf ("Vowels in '%s': ",str);
  pch = strpbrk (str, key);
  while (pch != NULL)
  {
    printf ("%c " , *pch);
    /* 也可以直接輸出字串 */
    printf("\noutput=%s\n", pch);
    pch = strpbrk (pch+1,key);
  }
  printf ("\n");
  system("pause");
  return 0;
}

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/*
*
* Author      : appleboy
* Date        : 2010.04.01
* Filename    : strtok.c
*
*/

#include "string.h"
#include "stdlib.h"
#include "stdio.h"

int main()
{
  char str[]="00:22:33:4B:55:5A";
  char *delim = ":";
  char * pch;
  printf ("Splitting string \"%s\" into tokens:\n",str);
  pch = strtok(str,delim);
  while (pch != NULL)
  {
    printf ("%s\n",pch);
    pch = strtok (NULL, delim);
  }      
  system("pause");
  return 0;
}

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#include <stdio.h>
#include <stdlib.h>
int bitcount(unsigned int);
int main(){
    int count = 0, a;
    a = 1023;
    count = bitcount(a);
    printf("%d有%d個位元為1\n\n", a, count);

    system("pause");
    return 0;
}
int bitcount(unsigned int n)
{
   int count = 0 ;
   while (n)
   {
      count++ ;
      n &= (n - 1) ; //關鍵演算之處
   }
   return count ;
}

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int main(void)
{
     int *a,*b;
     a=1;
     b=1;
     printf("%d\n",a+b);
     return 0;
}

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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int leap(int year);
int leap(int year)
{  
  if((year%4)==0 && (year%100)!=0 || (year%400) ==0)
  {
    printf ("%d是閏年\n",year);
  }
  else
  {
    printf ("%d不是閏年\n",year);
  } 
}
int main(int argc,char *argv[])
{
  char *p;  
  char year[20];
  printf("請輸入您要查詢的年份『輸入exit離開』: ");
  while(fgets(year, sizeof(year), stdin))
  {
    if ((p = strchr(year, '\n')) != NULL)
      *p = '\0';  
    if(!strcmp("exit", year))
    {
      break;
    }
    leap(atoi(year));   
    printf("請輸入您要查詢的年份『輸入exit離開』: ");
  }

  return 0;
}

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#include <stdio.h>
struct st {
   char *name;
   int age;
   double height;
};

struct st St_Array[]= {  /* AN ARRAY OF structs */
   { "Jr.",     4,  34.20 },  /* St_Array[0] */
   { "Suzie",  23,  69.75 },  /* St_Array[1] */
};

int main()
{
   long double LD_Array[] = { 1.3, 501.09, 0.0007, 90.1, 17.08 };

   printf("\nNumber of elements in LD_Array = %d",
           sizeof(LD_Array) / sizeof(LD_Array[0]));

   /****  THE NUMBER OF ELEMENTS IN THE St_Array. ****/

   printf("\nSt_Array has %d elements",
           sizeof(St_Array)/sizeof(St_Array[0]));

   /****  THE NUMBER OF BYTES IN EACH St_Array ELEMENT.  ****/
   printf("\nSt_Array[0] = %d", sizeof(St_Array[0]));

   /****  THE TOTAL NUMBER OF BYTES IN St_Array.  ****/   
      printf("\nSt_Array=%d", sizeof(St_Array));
   return 0;

}