implementing password complexity

[rahul_p]

hi can i get help to write code for password complexity?when a user logs in,the code should check for something like this:
while(*pw){
if( *pw => 'A' && *pw <= 'Z' )
uc=1;
else if( *pw >= 'a' && *pw <= 'z' )
lc=1;
else if( *pw >= '0' && *pw <= '9' )
num=1;
pw++;
}
the code should also check for a minlen of 6 and maxlen of 12.

thanks