﻿ Comparisons
 Comparisons
 It is often necessary to compare one value to another and make a decision based on the result. XPL0 uses the following symbols to make comparisons:           =   Tests for equal values.         #   Tests for not equal values.         <   Tests if the first value is less than the second.         >   Tests if the first value is greater than the second.         >=  Tests if the first value is greater than or equal to the second.         <=  Tests if the first value is less than or equal to the second.   Here are some expressions containing comparison operators:           X = 3         A < 0.91         (X+1) >= Y   We have already seen an example of how XPL0 uses comparisons to make decisions. In the number guessing program, one of two statements were executed depending on a comparison:           if Guess > Number then Text(0, "Too high")         else Text(0, "Too low")   If the Guess was greater than the Number then it was "Too high"; otherwise it was "Too low".   XPL0 evaluates a comparison to true or false. These expressions evaluate to true:           55 > 23         (3*4) # (3+4)   These expressions evaluate to false:           (2+2) = 5         -33.3 > -4.5   WARNING: Since XPL0 treats all 16-bit integers as signed,           \$F000 > \$A000   is true, but         \$F000 > \$7000   is false.   Converting the hex to decimal makes the reason apparent:           -4096 > -24576   is true, and         -4096 >  28672   is false.