powers h define sqrx xx define cubex xx
例 文件包含举例 /* powers. h */ #define sqr(x) ((x)*(x)) #define cube(x) ((x)*(x)) #define quad(x) ((x)*(x)*(x)) /*ch 8_10. c*/ #include <stdio. h> #include "d: fengyibkcpowers. h" #define MAX_POWER 10 void main() { int n; printf("numbert exp 2t exp 3t exp 4n"); printf("----t-----t------n"); for(n=1; n<=MAX_POWER; n++) printf("%2 dt %3 dt %4 dt %5 dn", n, sqr(n), cube(n), quad(n)); }
例:分析下面程序的运行结果。 #include <stdio. h> #define NUM ok void main() { int a, b; float c, d; a=1; b=4; c=4. 2; d=5. 4; #ifdef NUM printf(”A=%dn B=%fn", a, b); #else printf(”C=%fn. D=%fn", c, d); #endif }
#include <stdio. h> #define R 1 void main() { float c, r, s; printf ("input a number: "); scanf("%f", &c); #if R r=3. 14159*c*c; printf("area of round is: %fn", r); #else s=c*c; printf("area of square is: %fn", s); #endif }
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