Double w = console. read()；
Conseil Write ("Please enter the height (m):");
Double h = console. read()；
Double body mass index = w/h * 2；;
If (Body Mass Index & GT20 & Body Mass Index <25)
{
Console. Write ("normal");
}
other
{
Console. Write ("exception");
}
Because I don't have a code environment here, this is the general idea. When you write, you should pay attention to grammar and so on.