The == operator tests whether two values are exactly the same. If you test two integers then the test is obvious; for example, if x is 2 and y is 3, then x == y is obviously false. However, two real numbers may not be the same even when you think so:
double x = 1.000001 * 1000000000000; double y = 1000001000000; if (x == y) std::cout << "numbers are the same";
The double type is a floating-point type held in 8 bytes, but this is not enough for the precision being used here; the value stored in the x variable is 1000000999999.9999 (to four decimal places).
The != operator tests if two values are not true. The operators > and <, test two values to see if the left-hand operand is greater than, or less than, the right-hand ...
