switch statement with basic math problem

[thejew19]

The issue i am having is initializing the math problem. cannot use string or if. must be able to just put in a simple math problem 8+8 and it will display the answer 16

#include <iostream>
#include <cassert>
#include <cmath>

using namespace std;

int main()
{
     char a, b;
     float x, y, z;

     cout << "1. Simple math expression evaluation." << endl;
     cout << "2. Exit. " << endl;
     cout << "Select an option: ";
     cin >> a;
     cout << endl;

     switch(a)
     {
          case '1':
               cout << "Enter a simple math expression: " << endl;
               cin >> b;

               switch(b)
               {
               case '1': (x + y == z);
                    cout << x << " + " << y << " = " << x + y;
                    cout << z << endl;
                    break;
               }
          default:
               cout << "Goodbye!" << endl;
     }

     return (0);
}

[jonnin]

not sure exactly what you want, but you need to either read in or assign x,y, and z. All 3 are being used uninitialized.

[keskiverto]

What is the user expected to type?

((42 + 7 )*( 8/4))/ 7

OR

n o m

where n and m are integers and o is one of the operators: + - / *

[Ganado]

On line 26, you have (x + y == z);
This isn't doing anything useful. Nothing. Nada. It is making a comparison of the addition of two uninitialized variables to a third, uninitialized variable.

By the way, variable names like "a" and "b" are very unclear names.

x, y, and z are all still uninitialized when you try to display them.

I'll start you off with this:

float x, y, z;
char math_operator;
cout << "Enter a simple math expression (ex: 3 + 2): " << endl;
cin >> x >> math_operator >> y;
switch (math_operator)
{
    case '+':
        z = x + y;
        // ...
        break;

    //case default: // etc.
}

[thejew19]

thank you. i was having problem with initializing into the nested switch or getting the math problem to work.

[thejew19]

the issue i am having now is that no answer is displaying when i do the math part.

#include <iostream>
#include <cassert>

using namespace std;

int main()
{
     char option_1, math_operator;
     float x, y, z;

     cout << "1. Simple math expression evaluation." << endl;
     cout << "2. Exit. " << endl;
     cout << "Select an option: ";
     cin >> option_1;
     cout << endl;

     switch (option_1)
     {
          case '1':
               cout << "Enter a simple math expression: " << endl;
               cin >> x >> math_operator >> y;
               break;
          case '2':
               cout << "Goodbye!" << endl;
               break;

               switch (math_operator)
               {
               case '+':
                    z = x + y;
                    cout << z << endl;
                    break;
               case '-':
                    z = x - y;
                    cout << z << endl;
                    break;
               case '*':
                    z = x * y;
                    cout << z << endl;
                    break;
               case '/':
                    assert(y);
                    z = x / y;
                    cout << z << endl;
               }
          default:
               cout << "Invalid choice!" << endl;
     }

     return (0);
}

[Ihatov]

Your second switch is floating in vacuum.

Clearly, the switch at line 28 should be after line 22 (inside case '1').