what is the meaning of "==" this sign

Answer 1

This operator tests if the two operands are equals and return true (1) if they are, false (0) if they aren't.

Answer 2

== is used to check if LHS and RHS are equal, and it differs from = as"=" is used to assign a value to a variable.

Answer 3

If you are comparing two values you would use == and if you want to assign values you use =. An example would be:

x=2+2 //assignment
if(a==b)
{ do something}

Answer 4

Equal to