#include <stdio.h>
float fun(float x, float y);/*porpotypes declaration*/
float sum(float x, float y)/*define*/
{
float s = 0;
s = x+y;
return s;
}
void main()
{
extern float a, b; /*declare extern variables*/
float s;
s = sum(a, b);
printf("s = %.2f\n",s);
}
float a = 10, b = 20; /*define extern variables*/
转载于:https://my.oschina.net/u/241930/blog/403446