Logical functions

  We have discussed the If, 'While and For' Statements, and have used expressions within our syntax i.e.
 
        If ( expression)
          Statement 1;
        else
          Statement 2;
 
        do
        statement;
        while (expression);
 
        for (init;expression;alter)
        statement;
 
        while ( expression)
        statement;

We tended to restrict ourselves to simple expression i.e A == 5 etc. This is a simplification of what an expression really is. The equality sign indicates a logical identity i.e. true or false. Many other logical expressions could yield true or false .The most common ones are AND '&&', OR  '||' and NOT '!' , these behave identical to there truth table counterparts .  Therefore a valid expression could be

        (age > 40) &&( term < 10) 
  
  If age is greater than 40 and term is less than 10 then it is true or false 
 
        (age > 40) || (term <10)
  If age is greater than 40 or term is less than 10 then it is true or false 
 
        (age !> 40) || (term <10)
 
  If age is not greater than 40 or term is less than 10 then it is true or false