Relational Expressions
Logical not “!” symbol inverts the truth of an expression
C uses symbols to make comparisons between two values (either constants or variables): <, >, <=, >=, !=, ==
e.g., 10 != 10, 5 < 5, 11 == 10, 10 < 5 || 11 >= 10, 5 == 5 && 15 <= 45, !(5 < 5)