程序中逻辑表达式从终端输入, 演示程序以用户与计算机的对话方式执行 根据用户输入的逻辑表达式,判别其是重言式还是矛盾式,或两者都不是 若都不是则与用户交互.-Process logical expression from the terminal input, demo program to the user' s dialogue with the computer implementation in accordance with user input logic expressi