8
8.1
8.2
8.3
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8.1
8.1.1
8.1.2
8.1.3
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8.1.1
1
#define
define”
2
1
2
3
[8.1]
/*AL8_1.C*/
/* */
#define PI 3.1415926 /*PI3.1415926*/
main()
{ float radius,length,area,volume;
printf("Input a radius,");
scanf("%f",&radius);
length=2*PI*radius; /**/
area=PI*radius*radius; /**/
volume=PI*radius*radius*radius*3/4; /**/
printf("length=%.2f,area=%.2f,volume=%.2f\n",length,area,volume);
}
[]
3
1
21
3
4#define
5
6
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8.1.2
#define EOF -1 /**/
#define NULL 0 /**/
#define MIN 1 /**/
#define MAX 31 /**/
#define STEP 2 /**/
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8.1.3
1
#define ()
2
1()
2
3
1
2
3
1
2
311
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8.2
1
2
include,include <>
1
2
3
4
1#include
2 h”head
3nn
4
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8.3
8.3.1 #ifdef ~ #endif #ifndef ~ #endif
8.3.2 #if ~ #endif
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8.3.1 #ifdef ~ #endif #ifndef ~ #endif
1
ifdef
1
[ else
2]
endif
2 #define12
1int
2
3#ifndef ~ #endif
#ifdef ~ #endif
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8.3.2 #if ~ #endif
1
if
1
[ else
2]
endif
20 12
[8.2] *
/*AL8_2.C*/
#define PASSWORD 0 /**/
main()
{ ……
/**/
#if PASSWORD /**/
……
#else /**/
……
#endif
……
}
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