谁帮忙做一个程序：用c语言做一个计算器

#include
int main()
{
void act1(double,double),act2(double,double),act3(double,double),act4(double,double);
char c;
double a,b;
int i;
while(1)
{
system("cls");
printf("输入两个数来进行四项运算。");
scanf("%lf",&a);
c=getchar();
scanf("%lf",&b);
switch(c)
{
case'+':act1(a,b);getch();break;
case'-':act2(a,b);getch();break;
case'*':act3(a,b);getch();break;
case'/':act4(a,b);getch();break;
case'0':exit(0);
default:putchar('\a');
}
}
return 0;
}
void act1(double x,double y)
{
int z;
(int)(z=x+y);
printf("%0.0lf+%0.0lf%=%d\n",x,y,z);
}
void act2(double x,double y)
{
int z;
(int)(z=x-y);
printf("%0.0lf-%0.0lf=%d\n",x,y,z);
}
void act3(double x,double y)
{
printf("%0.1lf*%0.1lf=%0.1lf\n",x,y,x*y);
}
void act4(double x,double y)
{
printf("%0.1lf/%0.1lf=%0.3lf\n",x,y,x/y);
}