Sorry for the question, I have been doing Python and JS too much and am coming back to C++ now to assign an array.
How can it be done easier than this:
float* d1 = (float*)calloc(4,sizeof(float));
d1[0] = 1;
d1[1] = 2;
d1[2] = 3;
d1[3] = 4;
I am used to d1 = [1,2,3,4] and cannot wrap my head around it...
I see the following options for creating an array of floats.
Option 1
Use a regular array.
float d1[] = {1.0f, 2.0f, 3.0f, 4.0f};
or
float d1[4] = {1.0f, 2.0f, 3.0f, 4.0f};
Option 2
Use std::array.
std::array<float, 4> d1{1.0f, 2.0f, 3.0f, 4.0f}
Option 3
Use std::vector.
std::vector<float> d1{1.0f, 2.0f, 3.0f, 4.0f}
Unless there is a strong reason, prefer to use std::array or std::vector. std::array is appropriate if you know the size of the array at compile time. std::vector is appropriate if you don't know the size of the array at compile time.
One of the main benefits of using std::array or std::vector is that you have the ability to find out the size of array when the variable is used in a function call. If you use a regular array, the array decays to a pointer. You have to pass the size in another argument to help the function prevent accessing the array using an out of bounds index.
Try this code out :
float array[] = {1.0f,2.0f,3.0f,4.0f};
This code creates a simple array of 4 elements . Upon initialization , the arrays is the following contents : 1,2,3,4 . Hope this helps .
If the values are known at compile time
float d1[4] = {1.0f, 2.0f, 3.0f, 4.0f};
or
std::array<float, 4> d1 {1.0f, 2.0f, 3.0f, 4.0f}; // since C++11
The simple way is, assuming values are generated at run time,
std::array<float, 4> d1; // or float d1[4]
for (int i = 0; i < 4; ++i) d1[i] = i+1.0f;
// or, instead of the loop, since C++11
std::iota(std::begin(d1), std::end(d1), 1.0f); // iota() specified in <numeric>
or (if the number of elements is not known until run time)
std::vector<float> d1(number);
for (int i = 0; i < number; ++i) d1[i] = i+1.0f;
// or, instead of the loop, since C++11
std::iota(d1.begin(), d1.end(), 1.0f);
::std::array<float, 4> d1{1.0f, 2.0f, 3.0f, 4.0f};mallocfamily of functions in C++. So don't.