C :: Changing Order Of Numbers In Array

I want to write a programm that will reverse the order of the numbers in an array (e.g. as an input 1,2,3.5,4 and as an output i want 4,3.5,2,1) . But i have to problems:

1) I do not know how to properly change the type of a numbers inside an array from int to float or double, changing int to float in front of the a[10], does not change anything instead the code does not want to compile then.

2) I also want to make an array of a number of elements typed by a user with use of a "do" loop and how to put this parameter in the code.

Here is my code:

Code:

// ConsoleApplication3.cpp : Defines the entry point for the console application.//
#include "stdafx.h"
int _tmain(int argc, _TCHAR* argv[]) {
int a[10], i, n;
int pom;
do {
printf("number of elements in an array a: n = ");

[Code]...