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，更多的情况下，既非重言式，也非矛盾式。试写一程序，通过真值表判断一个逻辑表达式属于那一类。-If a logical expression for the changes in the yuan's value for a true, as tautology; Conversely, if the changes for the yuan's value for a leave, they were called contradiction; However, the more the circumstances, neither tautology, but also of non-contradiction. Try to write a procedure for the adoption of a truth table judgment logic expressions belong into that category.