c++ typecast array

Question

How can one typecast an array of int to an array of float? Thanks.

Answer 1

#include <algorithm>
#include <iostream>

#define N 50

int main() {
    int intArray[N] = { ... };
    float floatArray[N];
    std::copy(intArray, intArray + N, floatArray);
    std::cout
        << std::boolalpha << std::equal(intArray, intArray + N, floatArray)
        << std::endl;
    return 0;
}

Answer 2

If you have an array of ints, what you basically have is a block of N ints stored contiguously in memory. An array of floats, however, would be N floats stored contiguously in memory, i.e. an entirely different sequence of bits in memory. Additionally, floating point values are represented in binary in an entirely different way than integral values. In fact, you can't even be sure that an int is the same size as a float.

So therefore, you either have to cast each int to a float separately as you process the array, or else create an entirely different array by copying the original array.

For example, you could simply convert each int to a float lazily as you process the array:

int array[100];
// ... fill array with some values

for (int i = 0; i < 100; ++i)
{
  float f = array[i]; // implicit conversion here 
  // now do something with this float
}