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º¯ÊýÃû: abs ¹¦ ÄÜ: ÇóÕûÊýµÄ¾ø¶ÔÖµ
ÓÃ ·¨: int abs(int i);
³ÌÐòÀý:
#include <stdio.h>
#include <math.h>
int main(void)
{
int number = -1234;
printf("number: %d absolute value: %d\n", number, abs(number));
return 0;
}
º¯ÊýÃû: atof
¹¦ ÄÜ: °Ñ×Ö·û´®×ª»»³É¸¡µãÊý
ÓÃ ·¨: double atof(const char *nptr);
³ÌÐòÀý:
#include <stdlib.h>
#include <stdio.h>
int main(void)
{
float f;
char *str = "12345.67";
f = atof(str);
printf("string = %s float = %f\n", str, f);
return 0;
}
º¯ÊýÃû: atoi
¹¦ ÄÜ: °Ñ×Ö·û´®×ª»»³É³¤ÕûÐÍÊý
ÓÃ ·¨: int atoi(const char *nptr);
³ÌÐòÀý:
#include <stdlib.h>
#include <stdio.h>
int main(void)
{
int n;
char *str = "12345.67";
n = atoi(str);
printf("string = %s integer = %d\n", str, n);
return 0;
}
º¯ÊýÃû: atol
¹¦ ÄÜ: °Ñ×Ö·û´®×ª»»³É³¤ÕûÐÍÊý
ÓÃ ·¨: long atol(const char *nptr);
³ÌÐòÀý:
#include <stdlib.h>
#include <stdio.h>
int main(void)
{
long l;
char *str = "98765432";
l = atol(lstr);
printf("string = %s integer = %ld\n", str, l);
return(0);
}
º¯ÊýÃû: bsearch
¹¦ ÄÜ: ¶þ·Ö·¨ËÑË÷
ÓÃ ·¨: void *bsearch(const void *key, const void *base, size_t *nelem, size_t width, int(*fcmp)(const void *, const *));
³ÌÐòÀý:
#include <stdlib.h>
#include <stdio.h>
#define NELEMS(arr) (sizeof(arr) / sizeof(arr[0]))
int numarray[] = {123, 145, 512, 627, 800, 933};
int numeric (const int *p1, const int *p2)
{
return(*p1 - *p2);
}
int lookup(int key)
{
int *itemptr;
/* The cast of (int(*)(const void *,const void*))
is needed to avoid a type mismatch error at
compile time */
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int func(x)
{
int countx = 0;
while(x)
{
countx
++;
x = x&(x-1);
}
return countx;
}
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#ifndef C_EXAMPLE_H
#define C_EXAMPLE_H
#ifdef __cplusplus
extern "C"
{
#endif
int add(int x, int y);
#ifdef __cplusplus
}
#endif
#endif
---------------------------------
//cExample.c
#include"cExample.h"
int add(int x, int y)
{
return x + y;
}
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#ifdef __cplusplus
extern "C" {
#endif
//Ò»¶Î´úÂë
#ifdef __cplusplus
}
#endif
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