The Switch Statement

The structure of a switch statement is the following:

 switch(expression) {
    case   :
    statements
    break;

    case  :
    statements
    break;

    //More cases...

    default :
    statements
}

The case to be executed is determined based on the value of the constant_expression. In other words, you may have an int, char, etc…They must be constants. The break statement once encountered breaks out of the switch statement. In other words, if you don’t include the break statement in one of your cases, it will simply execute the following cases until it reaches a break or the end of switch statement. The default case is simply all other cases not covered.

An example would be…

 cin >> number;
switch(number) {
     case 1:
     cout << "One\n";
     break;
     case 2:
     case 3:
     cout << "My favorite numbers...\n";
     break;
     default:
     cout << "What!?\n";
}

In other words, if the user chooses 1, they will encounter case 1, if they choose 2 or 3, they receive "My favorite..." statement, else they receive "What!?".

Another example comparing an if else statement with a switch statement

Imagine a banking program in which the teller gives the program an integer value to perform a different action. Each action determines the reward the user receives.

1 - Gold Reward... Receives $100 reward plus all the other rewards
2 - Silver Reward... Received $50 reward plus the Bronze Reward
3 - Bronze Reward... Received $25 reward
* - Deduct $100 from their account

*Denotes any other value

How would this look like with a if and else statement?

cin >> action;

if ( action == 1 ) {
     //Give Gold Award
     //Give Silver Reward
     //Give Bronze Reward }
else if ( action == 2 ) {
     //Give Silver Reward
     //Give Bronze Reward }
else if ( action == 3 ) {
     //Give Bronze Reward }
else {
     //Deduct $100 from their account }
}

What about with a switch statement?

 cin >> action;

switch(action) {
     case 1:
     //Give Gold Reward
     case 2:
     //Give Silver Reward
     case 3:
     //Give Bronze Reward
     break;
     default:
     //Deduct $100 from their account
}

In other words, once action satisfies one case, it keeps executing the statements until it reaches the break statement which breaks out of the switch statement. Wouldn't this be much easier to for a reader to understand? Most likely in certain cases.

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The If Statement

An example is as follows

int x;
if ( condition ) x = 50; //If condition returns TRUE, assign 50 to X.

In other words, if the condition you provide returns a boolean value ( is a value that returns either TRUE or FALSE ) TRUE, then the following statements enclosed with {}’s are executed (no need if only one statement follows the if statement).


You may use the following operands in your conditions…
== – EQUAL TO
!= – NOT EQUAL TO
< - LESS THAN
<= - LESS THAN OR EQUAL TO
> – GREATER THAN
>= – GREATER THAN OR EQUAL TO

Here is an actual example.

int number;
cin >> number;
if ( number == 50 ) {
cout << "Congratulations! You picked the right number!" << endl;
}

In other words, if the user typed in 50, the if statement will be true and print the following line to the screen.

The If and Else

Let's say we want to output something if it was false.

int number;
cin >> number;
if ( number == 50 ) {
cout << "Congratulations! You picked the right number!" << endl;
}
else {
cout << "Sorry! You were wrong!" << endl; //Second Statement
}

Then, if the user didn't type in 50, it would output the second statement.

The If, Else-If, and Else

What if we wanted to check other conditions as well?

int number;
cin >> number;
if ( number == 50 ) {
cout << "Congratulations! You picked the right number!" << endl;
}
else if ( number > 50 ) {
cout << "Sorry! You were over!" << endl; //New Statement
}
else {
cout << "Sorry! You were way off!" << endl;
}

In other words, this one has a different output if the user entered a number larger than 50! If the user didn't choose 50, or a number larger than fifty, then the last else statement would be executed.


Keep in mind that you may add multiple else if statements! Just remember to have good coding style in order for any future reader to understand what statements pertain to what if condition. The way my code is written is a really good way of styling your code as its easy to read and follow!

So what now?

If you have trouble don't be afraid to post below any questions, comments, or concerns!

In the next tutorial expect to learn how to use If, Else If, and Else statements in more detail!

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