CS 111 - 3/10/15 College Of Engineering: Advising Sign-up Week - Look for information on your advisor's door - For a list of advisors, stop by 905 SEO or check email Office hours for Prof. Troy will end on Tuesday 3/10 and Thursday 3/12 at 12:20pm. Multiple conditions: Boolean Operators Join the results from multiple conditions into a single boolean value AND, OR, NOT operations AND: && Syntax: && The result of the AND operation will be true if both and are true; otherwise, the result will be false. Example: Is the value of a variable in a range of numbers? Check if val1 is between 1 and 10 inclusive if ( ( val1 >= 1 ) && ( val1 <= 10 ) ) { System.out.println ("val1 is in the range from 1 to 10"); } else { System.out.println ("Val1 is NOT in the range from 1 to 10"); } OR Operation: || Syntax: || The result of the OR operation will be true if either or is true; otherwise, the result will be false. Example: Is the value of a variable outside a range of numbers? Check if val1 is not in the range from 1 and 10 inclusive if ( ( val1 < 1 ) || ( val1 > 10 ) ) { System.out.println ("val1 is NOT in the range from 1 to 10"); } else { System.out.println ("Val1 is in the range from 1 to 10"); } To help people remember and/or use AND and OR operations, learning their "Truth Tables" is a valuable tool ex1 ex2 ! ex1 && ex2 ex1 || ex2 ============================================= true true ! true true true false ! false true false true ! false true false false ! false false x = 3; y = 2; z = 1; if ( ( x <= 5 ) || ( y >= 4 )) { z = z + 1; } else { z + z + 2; } NOT: ! Syntax: ! The result of the NOT operation will return true if the is initially false; Otherwise, it will return false if the is initially true. // check if the value in val1 is less than or equal to 5 if ( ! (val1 > 5) ) While not could be used in the above case, most programmers will not use it there. However, a more common use would be: Check if val1 is not in the range from 1 to 10 inclusive if ( !(( val1 >= 1 ) && ( val1 <= 10 )) ) { System.out.println ("val1 is NOT in the range from 1 to 10"); } else { System.out.println ("Val1 is in the range from 1 to 10"); } WARNING: THE FOLLOWING DOES NOT WORK!!!!! if ( 1 <= val1 <= 10 ) The above code attempts to compare a boolean value with an integer value, which is UNDEFINED in most computer languages.