Not many people are going to go through all that, but:
In your functions you have a common problem: Unintialized variables.
http://en.wikipedia.org/wiki/Uninitialized_variable
Just looking at your last two functions, you have the same problems as before:
In your totalAmount() function,
amount1,
total, and
quantity1 have junk values in them.
In your menuConfirmation() function,
userName's indices,
contactNumber, and
userAddress all have junk in them as well.
What are you expecting to be in them? You must realize that these local variables have
nothing to do with any other functions you're calling totalAmount() from.
The scope of a variable is where a variable is defined. The
quantity1 defined in your mealOne() function has no relation to your
quantity1 variable in your totalAmount function.
I would also read the site's tutorial on functions.
http://www.cplusplus.com/doc/tutorial/functions/
You can pass values you want to use through the function's parameters.