c++入门，有没有人能帮我看看为啥错了？

include
using namespace std;
int main()
{
float a,b,c;
char d;
int e;
cin>>a>>b;
cin>>d;
if(b==0&&d=='/')
cout"abcd";
e=a;
c=e;
if(c==a&&d=='%')
cout"error!";
switch(d)
case'+':cout<<"a+b="<
case'-':cout<<"a-b="<
case'':cout<<"ab="< case'/':cout<<"a/b="<
default:break;
return 0;
}

1 include 处未正确引入头文件
2. cout 处 漏掉输出符号 <<
3 switch 是块 需将后续语句置于其所属块中， 否则仅对swich后的一条语句有效
4 case ‘’ 空字符无法识别

正确代码如下:

#include

using namespace std;

int main() {
float a, b, c;
char d;
int e;
cin >> a >> b;
cin >> d;
if (b == 0 && d == '/')
cout << "abcd";
e = a;
c = e;
if (c == a && d == '%')
cout << "error!";
switch (d) {
case '+':
cout << "a+b=" << a + b << endl;
break;
case '-':
cout << "a-b=" << a - b << endl;
break;
case '*':
cout << "ab=" << a * b << endl;
break;
case '/':
cout << "a/b=" << a / b << endl;
break;
default:
break;
}

return 0;
}