给这个c语言程序加注释，越详细越好？

#include<stdio.h>
void main()
{
float a,b,y;
char ch;
char s='c';
while(1)
{
if(s=='c'||s=='C')
{
system("cls");
printf("please input your operator：");
scanf("%f%c%f",&a,&ch,&b);
switch(ch)
{
case '+': y=a+b;break;
case '-': y=a-b;break;
case '*': y=a*b;break;
case '/': y=a/b;break;
}
printf("%.2f%c%.2f=%.4f\n",a,ch,b,y);
printf("C qingping,R tuichu :");
scanf("%c",&s);
}
else exit(0);
}
}

#include<stdio.h>
void main()
{
float a,b,y;
char ch;
char s='c';
while(1)//循环为真
{
if(s=='c'||s=='C')//如果s等于小写或者大写的C
{
system("cls");清屏
printf("please input your operator：");
scanf("%f%c%f",&a,&ch,&b);
switch(ch)//选择语句
{
case '+': y=a+b;break;//加法运算
case '-': y=a-b;break;//减法运算，下面一样
case '*': y=a*b;break;
case '/': y=a/b;break;
}
printf("%.2f%c%.2f=%.4f\n",a,ch,b,y);
printf("C qingping,R tuichu :");
scanf("%c",&s);//问你是否清屏
}
else exit(0);
}
}