public class BB {
public BB(boolean isUppperCase){
char start = isUppperCase? 'A':'a';
char end = isUppperCase? 'Z':'z';
while(start <= end){
System.out.print(start);
start++;
}
System.out.println();
}
public BB(){
this(false);
}
public static void main(String[] args) {
new BB();//默认输出小写字目标
System.out.println();
new BB(true);//大写就传参数true
}
}
-----------testing
abcdefghijklmnopqrstuvwxyz
ABCDEFGHIJKLMNOPQRSTUVWXYZ