谁知道我这C语言的计算器的程序哪里错误了？

Question

#include <stdio.h>
main()
{
double n1=0.0;
double n2=0.0;
char o=0;
printf("请输入：");
scanf("%lf%c%lf",n1,o,n2);
switch(o)
{
case'+':
printf("=%lf\n",n1+n2);
break;
case'-':
printf("=%lf\n",n1-n2);
break;
case'*':
printf("=%lf\n",n1*n2);
break;
case'/':
if(n2=0)
printf("输入错误/n");
else
printf("=%lf\n",n1/n2);
break;
case'%':
if(n2=0)
printf("输入错误/n");
else
printf("=%ld\n",(long)n1%(long)n2);
break;
default:
printf("计算不在范围之内");
break;

}
}

Answer 1

scanf("%lf%c%lf",n1,o,n2);//这句错了。
scanf("%lf%c%lf",&n1,&o,&n2);//给地址赋值，前面加&