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package learn;
public class ConditionalStatement {
public static void main(String[] args){
//if...else...语句
int one = 30;
if(one % 2 == 0){
System.out.println("one是偶数");
}else{
System.out.println("one不是偶数");
}
//if...else if...else...语句
int age=25;
if(age > 60){
System.out.println("老年");
}else if(age >= 40){
System.out.println("中年");
}else if(age >= 18){
System.out.println("少年");
}else{
System.out.println("童年");
}
//嵌套if语句
int score = 92;
String sex = "男";
if(score >= 90){
if(sex.equals("男")){//equals判断值是否相等
System.out.println("进入男子组决赛");
}else{
System.out.println("进入女子组决赛");
}
}else {
System.out.println("淘汰");
}
System.out.println();
System.out.println("=================================");
System.out.println("switch条件判断语句");
String today="日";//匹配时请注意today的类型
switch(today){
case "一":
case "三":
case "五":
System.out.println("The breakfast is baozi today");
break;
case "二":
case "四":
case "六":
System.out.println("The breakfast is youtiao today");
break;
default:
System.out.println("吃主席套餐");
}
System.out.println();
System.out.println("=================================");
System.out.println("while条件判断语句");
System.out.println("while语法: while(判断语句){循环条件}"
+ "执行过程:(1).判断语句是否成立(true or false).(2).条件成立,执行循环体");
//循环输出同一条语句
int i = 1;
int j = 1;
while(i <= 10){
System.out.println(i);
i++;
}
while(j <= 10){
System.out.println("I love imooc"+ j);
j++;
}
System.out.println();
System.out.println("=================================");
System.out.println("do...while条件判断语句");
System.out.println("do...while语法:do{循环语句}while(判断语句)"
+ "执行过程:(1). 先执行一遍循环操作,然后判断循环条件是否成立.(2). 如果条件成立,继续执行(1) 、(2),直到循环条件不成立为止"
+ "特点:先执行,后判断");
int sum = 0; // 保存 1-50 之间偶数的和
int num = 2; // 代表 1-50 之间的偶数
do {
//实现累加求和
sum += num;
num = num + 2; // 每执行一次将数值加2,以进行下次循环条件判断
} while (num <= 50); // 满足数值在 1-50 之间时重复执行循环
System.out.println(" 50以内的偶数之和为:" + sum );
}
}