Is it always necessary to use float literals when performing arithmetic on float variables in C++?

Question

I see a lot of C++ code that has lines like:

float a = 2;
float x = a + 1.0f;
float b = 3.0f * a;
float c = 2.0f * (1.0f - a);

Are these .0f after these literals really necessary? Would you lose numeric accuracy if you omit these?

I thought you only need them if you have a line like this:

float a = 10;
float x = 1 / a;

where you should use 1.0f, right?

Answer 1

You would need to use it in the following case:

float x = 1/3;

either 1 or 3 needs to have a .0 or else x will always be 0.