I have to make a menu and you choose which one you want by pressing 1 2 or 3, however, this is required:

"Check that the user has selected one of the available menu choices. If they have not, allow re-entry before the switch is executed"

my guess is to do:

if(medium!=1)
if(medium!=2)
if(medium!=3){

cout<< "Invalid entry, please reenter" << endl;

}

Unsure how to enable the user to reenter following an invalid entry.

While loop perhaps? I tried, but was unsuccessful because I was still not able to reenter the selection.

Here is my code:

float distance;
float air = 1100;
float water = 4900;
float steel = 16400;


cout << " 1 - Air 2 - Water 3 - Steel" << endl;
cin >> medium;

switch(medium){
case 1:
cout << " You have selected air \n" << endl;
cout << " How many feet will the sound wave travel in this medium? \n" << endl;
cin >> distance;

cout << " The total time it will take, in seconds, is " << distance/air << endl;
break;

case 2:
cout << " You have selected water \n" << endl;
cout << " How many feet will the sound wave travel in this medium? \n" << endl;
cin >> distance;

cout << " The total time it will take, in seconds, is " << distance/water << endl;
break;

case 3:
cout << " You have selected steel \n" << endl;
cout << " How many feet will the sound wave travel in this medium? \n" << endl;
cin >> distance;

cout << " The total time it will take, in seconds, is " << distance/steel << endl;
break;

}

return 0;
}

this is an example of how i got mine to work.. this problem was to insert a # between 2-9. my code above works for both inserting characters instead of numbers and any number outside of the 2-9 range.

hope that helps

Your code is fine, just add the condition to go back to the start of the switch in case no valid case is found, like this:

very quick question!

Goto is almost entirely outlawed in most school courses and is poor programming. You can wrap the menu in a loop that can then act as a counter controlled loop. I would strongly recommend avoiding the use of goto unless your intention is spaghetti code.

It's the most explicit representation of a jump operation in asm. This is C, not C++ or some managed fancy new language with internal spaghetti you can't even fathom.

i'd do it like this

Yeah, this is how I'd do it.