Thread: C++ Question

Hello, i got a problem with this question with my C++ lab reports, i was wondering if anyone could tell me why it isn't working properly, the code is:

Lab Exercise 3a

What output will be produced by the following code when embedded in a complete program?
Consider initial values for first_choice of 0, 1 and -1.

Code:

int x = first_choice++;
switch (first_choice + x)
{
  case 1: cout << "Waitrose\n" break;

  case 2: cout << "Sainsburys\n" break;

  case 3: cout << "Tesco\n" break;

  case 4: cout << "Asda\n" break;

  default: cout << "No shopping today!\n";
}

So i made this to figure out the answer:

Code:

#include "stdafx.h"
#include <string>
#include <iostream>

using namespace std;

int main()

int x = first_choice++;
switch (first_choice + x)
{
  case 1: cout << "Waitrose\n" break;

  case 2: cout << "Sainsburys\n" break;

  case 3: cout << "Tesco\n" break;

  case 4: cout << "Asda\n" break;

  default: cout << "No shopping today!\n";
}

return 0;

}

Anyone know why, i get illegal case and illegal break errors.

Thanks

I think the intent of your lab question was that you be the computer and reason the output for yourself. The question mentions that the code provided is not a complete program, so you'll have to revise the code accordingly if you're too lazy to think it through.

every statement must have a semicolon after it, so "cout << "Waitrose\n" break;" is considered one statement (which doesnt make sense). after your cout statement (before break) you need to tell the compiler that the statement is done, by inserting a semicolon.

it is actually easier to follow the example without doing any coding. there is no trick involved. for example, if first_choice is 0, x will be 0, so their sum is 0, and there is no case for this so it will execute the default case.

Originally Posted by nadroj

for example, if first_choice is 0, x will be 0, so their sum is 0, and there is no case for this so it will execute the default case.

Because of the first_choice++, first_choice will have been incremented when it gets to the switch statement, so:

x + first_choice = 0 + 1 = 1