由系统随机生成4张扑克牌，用户利用扑克牌的数字及运算符号“+”、“—”、“*”、“/”及括号“（”和“）”从键盘上输入一个计算表达式，系统运行后得出计算结果，如果结果等于24，则显示“Congratulation!”，否则显示“Incorrect!”-By the system randomly generated four playing cards, the number of users to poker and the operator symbols "+" ,"-" ,"*" ," /"　and parentheses " ("　and " )"　from the keyboard to enter a calculation expression , the system obtained after running the calculation results, if the result is equal to 24, then display " Congratulation!" , otherwise display " Incorrect!"