一个逻辑表达式如果对于其变元的任一种取值都为真，则称为重言式；反之，如果对于其变元的任一种取值都为假，则称为矛盾式；然而，更多的情况是，既非重言式，也非矛盾式。试写一个程序，通过真值表判别一个逻辑表达式属于上述哪一类-If a logical expression of its variables are either value is true, then known as tautology　the contrary, if its arguments are of any value to be false, then known as the contradiction　however more the case that neither tautology nor a contradiction. Try to write a program, through a logical expression truth table determine the type of the above