121/122/123/124.JAVA入门__String案例

String案例1

输入账号和密码，一共有三次输入机会。

package com.itheima;

import javax.swing.*;
import java.util.Scanner;

public class one_121 {
public static void main(String[] args) {
String admin = “xiaoming”;
String password = “123456”;
for (int i = 0; i < 3; i++) {

        System.out.println("请输入账号：");
        Scanner sc = new Scanner(System.in);
        String admin1 = sc.nextLine();
        System.out.println("请输入密码：");
        Scanner sc1 = new Scanner(System.in);
        String password1 = sc1.nextLine();


        if((admin1.equals(admin))&&(password.equals(password1))) {
            System.out.println("登陆成功");
            break;
        } else {
            if(i == 2){
                System.out.println("你没机会了");
            }else{
                System.out.println("账号或密码错误，你还有"+(2-i)+"次机会");
            }
        }
    }
    }
}

String案例2

输入字符串，并把其中的字符挨个输出出来
package com.itheima;

import java.util.Scanner;

public class one_122 {
public static void main(String[] args) {
System.out.println(“请输入字符串：”);
Scanner sc = new Scanner(System.in);
String s1 = sc.nextLine();
System.out.print("{ “);
for(int i=0;i if(i == s1.length()-1){
System.out.print(s1.charAt(i));
}else{
System.out.print(s1.charAt(i)+”,");
}
}
System.out.println(" }");
}
}

String案例3

统计输入的字符串里面大写，小写和数字的个数。

package com.itheima;

import java.util.Scanner;

public class one_123 {
public static void main(String[] args) {
System.out.println(“请输入:”);
Scanner sc = new Scanner(System.in);
String s1 = sc.nextLine();
int bigNumber = 0,smaNumber = 0,digNumber = 0;
for(int i=0;i if(‘a’<=s1.charAt(i)&&s1.charAt(i)<=‘z’){
smaNumber++;
}else if (‘A’<=s1.charAt(i)&&s1.charAt(i)<=‘Z’){
bigNumber++;
}else if (‘0’<=s1.charAt(i)&&s1.charAt(i)<=‘9’) {
digNumber++;
}

    }

    System.out.println("大写字母有："+ bigNumber);
    System.out.println("小写字母有："+ smaNumber);
    System.out.println("数字有："+ digNumber);

}

}