JAVA选择结构

package bai;

public class six {

public static void main(String[] args) {
	// TODO Auto-generated method stub
	int a = 89;
	if(a>=90) {
		System.out.println("优秀");
	}else if(a>=80){
		System.out.println("良好");
	}else if(a>=60) {
		System.out.println("及格");
	}else {
		System.out.println("不及格");
	}

}

}

package bai;

public class six2 {

public static void main(String[] args) {
	// TODO Auto-generated method stub
	int a = 3;
	if(a>0) {
		if(a>100) {
			System.out.println("a是大于一百的正数");
		}else {
			System.out.println("a是小于一百的正数");
		}
		
	}else {
		System.out.println("a是负数");

	}

}

}