9_6.cpp

C程序参考,简单易懂,是初学者不可少的参考资料

#include<stdio.h>
#include "f2.c"
main()
{
    float r=3.0,area;
    area=PI*r*r;
    PR(F,area);
}
/* build a header file f2.c
#define PI 3.1415926
#define PR printf
#define F "%f\n"     */