right use of switch(), case and break statements

Hello, I have a question about using the switch() statement: when I use more than one 'case' for a single action, should I 'break' all the cases or simply using a single 'break' will end all the cases? bad english + I don't know how to explain = let me explain with a sample :)

Code:

---

#include <conio.h>

int main()
{
int a=1;
switch(1)
    {
    case 0:
    case 1:
        {
        //whatever for 0 or 1
        }
    break;
    break;
   
    case 2:
        {
        //for 2
        }
    break;
    }
getch();
return 0;
}

---

That is, I have used 2 'case', for 0 and for 1; then should I use also twice 'break'? I see that the program runs without error, and also I have find on the net lots of codes that uses only one 'break' after start several 'case', that also works without error; sometimes I used also this method, only breaking one time at the end and my simple programs run without problem. I was wondering which is the right way to do it? Should I 'break' each 'case'?
Thank's in advance
niara

First, just to note:

Code:

---

switch(1)

---

Will always cause "case 1:" to fire. "case 0:" will never execute, nor will "case 2:".

Say I want to execute the same code for 1, 2, and 3:

Code:

---

switch(X) //X is an int or char variable
{
case 1: case 2: case 3: //Essentially the same thing you wrote with "case 0:" and "case 1:" above
        //Have some code
        break; //This break will cause us to "break out" of the switch statement
}

---

Therefore, in your example, only one break is necessary when you want to "break out". Since "case 0:" does not have a "break" before the next case, any code (if there was any) following "case 0:" would be executed, then the code will keep going into "case 1:", and then it hits the break. The second break will never ever be reached.

The choice to "break" a case is all dependent on whether you want one of your cases which is above another one to also execute the code below it, or not.

You may find some compilers will issue a "no path to this statement" type warning if you use 2 breaks.

Hello both, thank's for your time and help.
Epo: yes, I know what happens with my silly sample code, it was only for help me to explain the '(1st)case:(2nd)case: (1st)break;(second break is needed?)' part. but you have 'switched on' a light on my question: the 'break' stops the 'switch' statement, from a single and from multiple 'case' conditionals.
adrianxw: thank's for the observation. I'm using DevC++ and (for the moment) does not alert any error for that 'error', but I will have in mind.
Thank's both.
regards
niara

If you have understood just tell what would be output of following program

Code:

---

int main()
{
  int a=1;
  switch(a)
  {
    case 1:cout<<"First case";
    case 2:cout<<"Second case";
    case 3:cout<<"Third case";
  }
return(0);
}

---