C/C++µÄÌõ¼þ±àÒë
ÒÔΪÒÑ¾ÕÆÎÕÌõ¼þ±àÒ룬Ԥ±àÒëµÄÒªÁìÁË£¬½á¹û»¹ÊÇ´æÔںܶàÒÅ©µÄµØ·½£¬ËùÒÔ¹æÕûһϣº
Ìõ¼þ±àÒ룺
1
#ifdef _XXXX
...³ÌÐò¶Î1...
#else
...³ÌÐò¶Î2...
#endif
Õâ±íÃ÷Èç¹û±êʶ·û_XXXXÒѱ»#defineÃüÁÒå¹ýÔò¶Ô³ÌÐò¶Î1½øÐбàÒ룻·ñÔò¶Ô³ÌÐò¶Î2½øÐбàÒë¡£
2
#ifndef _XXXX
...³ÌÐò¶Î1...
#else
...³ÌÐò¶Î2...
#endif
ÕâÀïʹÓÃÁË#ifndef£¬±íʾµÄÊÇif not def¡£µ±È»ÊǺÍ#ifdefÏà·´µÄ×´¿ö£¨Èç¹ûûÓж¨ÒåÁ˱êʶ·û_XXXX£¬ÄÇôִÐгÌÐò¶Î1£¬·ñÔòÖ´ÐгÌÐò¶Î2£©¡£
3
#if ³£Á¿
...³ÌÐò¶Î1...
#elif<³£Á¿±í´ïʽ2>
...³ÌÐò¶Î2...
#elif<³£Á¿±í´ïʽ3>
...³ÌÐò¶Î3...
... ...
#else
...³ÌÐò¶Î2...
#endif
ÕâÀï±íʾ£¬Èç¹û³£Á¿ÎªÕ棨·Ç0£¬Ëæ±ãʲôÊý×Ö£¬Ö»Òª²»ÊÇ0£©£¬¾ÍÖ´ÐгÌÐò¶Î1£¬·ñÔòÖ´ÐгÌÐò¶Î2¡£
ÀýÈç:
#if defined(_PC) && defined(_SSE)
# ifdef DEBUG
# define __PC_VERIFY_ALIGNMENT__
# endif
# ifdef __PC_VERIFY_ALIGNMENT__
# define PC_VERIFY_ALIGN_ASSERT( ptr ) \
{\
if( ( ( (INT) ptr ) % 16) != 0 ) \
{\
debugf( NAME_Critical, TEXT("Unaligned PC data (0x%X)"), ptr ); \
DebugBreak(); \
}\
}
# else
# define PC_VERIFY_ALIGN_ASSERT( ptr )
# endif
#else
# define PC_VERIFY_ALIGN_ASSERT( ptr )
#endif
ÔÙ̸µ½Ô¤±àÒëÃüÁî:
Ô¤´¦ÀíÆ÷ָʾ·û
Í·Îļþͨ¹ýinclude Ô¤´¦ÀíÆ÷ָʾ·ûpreprocessor include directive ¶ø³ÉΪÎÒÃdzÌÐòµÄ
Ò»²¿·ÖÔ¤´¦ÀíÆ÷ָʾ·ûÓÃ# ºÅ±êʶÕâ¸ö·ûºÅ½«·ÅÔÚ³ÌÐòÖиÃÐеÄ×îÆðʼһÁÐÉÏ´¦Àí
ÕâЩָʾ·ûµÄ³ÌÐò±»³Æ×öÔ¤´¦ÀíÆ÷preprocessor ͨ³£À¦°óÔÚ±àÒëÆ÷ÖÐ
#include ָʾ·û¶ÁÈëÖ¸¶¨ÎļþµÄÄÚÈÝËüÓÐÁ½ÖÖ¸ñʽ
#include <some_file.h>
#include "my_file.h"
Èç¹ûÎļþÃûÓüâÀ¨ºÅ< ºÍ> À¨ÆðÀ´±íÃ÷Õâ¸öÎļþÊÇÒ»¸ö¹¤³Ì»ò±ê׼ͷÎļþ²é
ÕÒ¹ý³Ì»á¼ì²éÔ¤¶¨ÒåµÄÄ¿Â
Ïà¹ØÎĵµ£º
Ô´Âë:
# include <stdio.h>
int main()
{
/* ¶¨Òå×Ö·ûÐͱäÁ¿£¬²¢¸øËüÃǸ¶³õÖµ */
char c1, c2, c3, c4, c5, c6, c7;
c1 = 'C';
c2 = 'h';
c3 = 'i';
c4 = 'n';
& ......
Ô´Âë:
# include <stdio.h>
int main()
{
/* sex´ú±íÊäѪÕßµÄÐÔ±ð£¬weight´ú±íÊäѪÕßµÄÌåÖØ£¬cubage´ú±íÊäѪÁ¿ */
int sex, weight, cubage;
printf("Çë¸ø³öÊäѪÕßµÄÐÔ±ð£¨Å®ÐÔΪ¸ºÊý£©ºÍÌåÖØ£º(ÓöººÅ¸ô¿ª)");
&nbs ......
Ô´Âë:
# include <stdio.h>
int main()
{
int i, j, k;
/* ±äÁ¿i´Ó0µ½4£¬±íʾËù»ÁâÐÎͼµÄµÚÒ»ÖÁµÚÎåÐÐ */
for(i = 0; i <= 4; i++)
{
/* ......
Ô´Â룺
/* ʹÓÃÑ¡Ôñ·¨ÅÅÐò */
# include <stdio.h>
int main()
{
int i, j, min, temp;
/* ¶¨ÒåÒ»¸öÕûÐ͵ÄһάÊý×é */
int array[10];
/* ÊäÈëÊý¾Ý */
printf("Please input ten integ ......
Ô´Â룺
# include <stdio.h>
/* ×Óº¯ÊýÉùÃ÷ */
int square(int x); // ʵÏÖÇ󯽷½ÖµµÄ×Óº¯Êý
int cube(int y); // ʵÏÖÇóÁ¢·½ÖµµÄ×Óº¯Êý
int main()
{
int m = 12;
int n = 4;
printf("%d %d\n", sq ......