变量声明

#include <stdio.h>



// Variable declaration:

extern int a, b;

extern int c;

extern float f;



int main () {



   /* variable definition: */

   int a, b;

   int c;

   float f;



   /* actual initialization */

   a = 10;

   b = 20;



   c = a + b;

   printf("value of c : %d \n", c);



   f = 70.0/3.0;

   printf("value of f : %f \n", f);



   return 0;

}