Java 分支结构 if语句的使用

public class IfClass {

    public static void main(String[] args) {
        // if(boolean 表达式){语句块}
        //boolean=true 执行语句块，反之不执行
        int score=56;
        if(score<60){
            System.out.println("不及格");
        }
        //if(boolean 表达式){语句块1}else｛语句块2｝
        //boolean=true 执行语句块1
        //boolean=false执行语句块2
        int score1=66;
        if(score1<60){
            System.out.println("不及格");
        }else{
            System.out.println("及格");
        }
                //基本数据类型判断是否相等用 ==
        //char
        char sex ='男';
        if(sex=='男'){
            System.out.println("请进男厕所");
        }else{
            System.out.println("请进女厕所");
        }
        //if(boolean 表达式){语句块1}else if(boolean 表达式)｛语句块2｝else if(boolean 表达式)｛语句块3｝....else{语句块n}
        if(sex=='男'){
            System.out.println("请进男厕所");
        }else if(sex=='女'){
            System.out.println("请进女厕所");
        }else{
            System.out.println("不进");
        }

        //声明三个变量取最大值：
        int a = 10;
        int b = 20;
        int c = 3;
        if(a>b){
            if(a>c){
                System.out.println("最大值为a");
            }else{
                System.out.println("最大值为c");
            }
        }else{
            if(b>c){
                System.out.println("最大值为b");
            }else{
                System.out.println("最大值为c");
            }
        }

        //输入一个数字，输出对应的星期数
        int weekday = 1;
        if(weekday == 1){
            System.out.println("星期一");
        }else if(weekday == 2){
            System.out.println("星期二");
        }else if(weekday == 3){
            System.out.println("星期三");
        }else if(weekday == 4){
            System.out.println("星期四");
        }else if(weekday == 5){
            System.out.println("星期五");
        }else if(weekday == 6){
            System.out.println("星期六");
        }else if(weekday == 7){
            System.out.println("星期天");
        }else{
            System.out.println("输入错误");
        }
    }

}