Telling my calculator to not divide by zero - c++

Question

I am making a calculator in C++ and it works fine except when I divide by zero. So I have an if statement saying to give the message "Error Divide buy zero" when a number is divide by zero. However the program still crashes.
Here is my code
#include <iostream>
using namespace std;
int main()
{
int a, b, d, s;
d == a/b
cout << "Enter first number\n";
cin >> a;
cout << "Enter second number\n";
cin >> b;
cout << "Select the operation you want\n";
cout << "1.Addition\n";
cout << "2.Subtraction\n";
cout << "3.Multiplication\n";
cout << "4.Division\n";
cin >> s;
switch (s)
{
case 1: cout << "Addition Selected\n"; a+b << endl; break;
case 2: cout << "Subtraction Selected\n"; a-b << endl; break;
case 3: cout << "Addition Selected\n"; a*b << endl; break;
case 4:
if (b==0)
{
cout << "Error Divide by Zero"<< endl;
}
else
{
cout << d << endl;
}
break;
default: cout << "Invalid Selection" << endl;
}
return 0;
}
On a secondary note when I select an operation it doesn't say that it was selected.

Answer 1

Your code has a lot of syntax errors.
Perhaps this can help you. This smartly avoids divide by zero and prints error message also.
#include <iostream>
using namespace std;
int main() {
int n1, n2, ans;
char op;
cin >> n1 >> op >> n2;
switch (op) {
case '+':
ans = n1 + n2;
break;
case '-':
ans = n1 - n2;
break;
case '*':
ans = n1 * n2;
break;
case '/':
if (n2) {
ans = n1 / n2;
break;
}
default:
cerr << "Invalid Input" << endl;
return 1;
}
cout << ans;
return 0;
}
See http://ideone.com/wa8QJG demo.

Answer 2

Your line
d == a/b;
Needs to be
d = a/b;
and it needs to move within the "else" clause. Otherwise the division by 0 error occurs before the print explaining the error.
You are also missing a print for the divide case and should add that.

Answer 3

There are many typos/syntax errors in your code.
Here is a working solution close to your code:
int main()
{
int a, b, d, s;
cout << "Enter first number\n";
cin >> a;
cout << "Enter second number\n";
cin >> b;
cout << "Select the operation you want\n";
cout << "1.Addition\n";
cout << "2.Subtraction\n";
cout << "3.Multiplication\n";
cout << "4.Division\n";
cin >> s;
switch( s )
{
case 1:
cout << "Addition Selected\n" << a + b << endl;
break;
case 2:
cout << "Subtraction Selected\n" << a - b << endl;
break;
case 3:
cout << "Multiplication Selected\n" << a * b << endl;
break;
case 4:
if( b == 0 )
{
cout << "Error Divide by Zero" << endl;
}
else
{
d = a / b;
cout << d << endl;
}
break;
default:
cout << "Invalid Selection" << endl;
}
return 0;
}