gcc命令行计算器项目基础（比bc的操作简单多了）

#include <stdio.h>
 
void addition(double _a,double _b);
void subtraction(double _a,double _b);
void multiplication(double _a,double _b);
void division(double _a,double _b);
 
void main()
{
    doublea,b;
 
   printf("请输入两个数:");
   scanf("%lf%lf",&a,&b);
   addition(a,b);
   subtraction(a,b);
   multiplication(a,b);
   division(a,b);
}
 
void addition(double _a,double _b)
{
   double_result;
    
   _result=_a+_b;
   printf("两数相加得:%5.3lf\n",_result);
}
 
void subtraction(double _a,double _b)
{
   double_result;
    
   _result=_a-_b;
   printf("两数相减得:%5.3lf\n",_result);
}
 
void multiplication(double _a,double _b)
{
   double_result;
    
   _result=_a*_b;
   printf("两数相乘得:%5.3lf\n",_result);
}
 
void division(double _a,double _b)
{
   double_result;
    
   _result=_a+_b;
   printf("两数相除得:%5.3lf\n",_result);
}