我让用户输入格式为
图像[1-4 位][0-1 字母]
例如:(有效名称)
image1
image1f
image1B
image2201
image2201a
无效
image (no number specified)
imagez (no number specified)
image12a1 (no digit permitted after letter)
image44aa (only one letter allowed after number)
如何检查是否输入了正确的格式?