从键盘输入两个数字(0~7)之间 （1）用16进制表示两个数的和 （2）用四位二进制表示两个数的差，结果一定>=0 （3）用两位十进制表示两个数的积 exemple:-keyboard input from the two figures (0 to 7) between (a) a 16-band, said the number two and (2) with four two binary said the number of poor, the results would cer