Making decisions with switch
We have already looked at if, which allows us to decide whether to execute a block of code based upon the result of its expression. But sometimes, a decision in C++ can be made in other ways that are better.
When we must make a decision based on a clear list of possible outcomes that don't involve complex combinations or wide ranges of values, then switch is usually the way to go. We can start a switch decision as follows:
switch(expression)
{
    // More code here
}
In the previous example, expression could be an actual expression or just a variable. Then, within the curly braces, we can make decisions based on the result of the expression or value of the variable. We do this with the case and break keywords:
case x:     //code for x     break;  case y:     //code for y     break;
As you can see, each case states a possible result...