Relational and Logical Operators

The relational and logical operators are used to produce Boolean (true/false) results and are often used together. In C/C++, any nonzero number evaluates as true. Zero is false. In C++, the outcome of the relational and logical operators is of type bool. In C, the outcome is a zero or nonzero integer. The relational operators are listed here:

The logical operators are shown here:

The relational operators compare two values, producing a Boolean result. The logical operators connect two Boolean values or, in the case of !, reverse a value. The precedence of these operators is shown here:

As an example, the following if statement evaluates to true and prints the line x is less than 10:

x = 9;
if(x < 10) cout << "x is less than 10";

However, in the following example, no message is displayed because both operands associated with && must be true for the outcome to be true:

x = 9;
y = 9;
if(x < 10 && y > 10) 
  cout << "This will not print.";