if的语法主要包括if单选则结构,if双选择结构,if多选择结构,if嵌套结构(存疑)
package struct;
import java.util.Scanner;
//If单选择结构
public class IfDemo1 {
public static void main(String[] args) {
Scanner scanner=new Scanner(System.in);
System.out.println("请输入文本");
String s = scanner.nextLine();
if(s.equals("yali")){
System.out.println(s);
}
System.out.println("End");
scanner.close();}
}
package struct;
import java.util.Scanner;
//If双选择结构
public class IfDemo2 {
public static void main(String[] args) {
//考试分数大于60分及格,小于60分不及格
Scanner scanner = new Scanner(System.in);
System.out.println("输入本次考试成绩");
int score = scanner.nextInt();
if(score>=60){
System.out.println("考试及格");
}else{
System.out.println("考试不及格");
}
scanner.close();
}
}
package struct;
import java.util.Scanner;
//If多选择结构
public class IfDemo3 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.println("请输入成绩");
int score = scanner.nextInt();
if(score==100){
System.out.println("此次考试满分");
}else if(score<100 && score>=90){
System.out.println("A级");
}else if(score<90 && score>=80){
System.out.println("B级");
}else if(score<80 && score>=70){
System.out.println("C级");
}else if(score<70 && score>=60){
System.out.println("D级");
}else if(score<60){
System.out.println("不及格");
}else{
System.out.println("成绩不合法");
}
scanner.close();
}
}
package struct;
import java.util.Scanner;
//If嵌套结构
//寻找一个数,在0~100之间
public class IfDemo4 {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
//输入一个数字判断 是否小于50 且 等于 25
System.out.println("请输入数字1~100");
int i = scanner.nextInt();
if (i <= 50){
System.out.println(i+"在1~50区间内");
if (i == 25){
System.out.println(i+"等于25");
}
}
scanner.close();
}}
