Write the if statement for bool, Int, float, and comparison between the pointer and zero value.

 

 

In this example, the comparison between float and zero is quite interesting.

Bool:

Bool flag;
If (flag = true)
Return;

 

INT:

Int var;
If (Var = 0)
{
Return;
}

Pointer variable:

Char * P;
If (P = nullptr)
{
Return;
}

Float:

Float cannot be compared directly with 0 due to precision issues, so there is a allowed range. In this range, we think it is equal, generally 10-6 power, small enough

There are several defined Precision values in C/C ++, which are defined in limit. H. flt_epsilon (floating point Precision) and dbl_epsilon (Long Double Precision) can be used directly)

For example, 1.0 + flt_epsilon! = 1.0.

Comparison between float and zero:

Float Var = 0.0;
If (-0.000001 <= var) & (VAR <= 0.000001f ))
{
Printf_s ("% F \ n", VAR); // The output VaR is 0.00000.
}