Master ()

{ int m，n；

Print ("Please enter length:");

m=scanf("%d "，& ampn)； //When the input format meets the requirements (that is, the integer "%d"), the return value of the scanf () function is e of, and the value of EOF is 1. If there is an error, the return value is 0.

If (m==o)

Printf ("Wrong again! \ n ")；

}