""

""
input "输入一个数"to a
do case
case a=1
"输入一个数"to x
"再输入一个数"to y
"和:" ,x+y
case a=2
"输入一个数" to x
"再输入一个数" to y
"差:" ,x-y
case a=3
"输入一个数" to x
"再输入一个数" to y
"积:" ,x*y
case a=4
"输入一个数" to x
"再输入一个数" to y
"商:" ,x/y
case a=5
return
otherwise
"错误"
endcase