JAVA基礎——循環結構題目2答案

package test;

public class Test1 {
	public static void main(String[] args) {
		int sum=0;
		for(int i=2;i<101;i=i+2)
		sum+=i;
		System.out.println(sum);
		
		
	}

}
package test;

public class Test2 {

	public static void main(String[] args) {
		
		for(int i=1;i<10;i++)
		{
			for(int j=1;j<10;j++)
			{
				System.out.print(i+"*"+j+"="+i*j);
				if(i*j<10)
					System.out.print("      ");
				else
					System.out.print("     ");
				if(j==9)
					System.out.println();
				
					
			}
			
		}
		
		System.out.println("*******************************************");
		for(int i=1;i<10;i++)
		{
			for(int j=1;j<i+1;j++)
			{
				System.out.print(i+"*"+j+"="+i*j);
				if(i*j<10)
					System.out.print("      ");
				else
					System.out.print("     ");
				if(j==i)
					System.out.println();
				
					
			}
			
		}

	} 
		
	
}
package test;

import java.util.Scanner;

public class Test3 {

	public static void main(String[] args){
		while(true)
		{
		System.out.println("請輸入一個數");
		Scanner in=new Scanner(System.in);
		int finger=in.nextInt();
		int i;
		for(i=2;i<=Math.sqrt(finger);i++)
			
			
			if(finger%i==0)
			
				{System.out.println("這不是素數");
			    break;
				}
			if(i>Math.sqrt(finger))
				System.out.println("這真是一個素數");
		
	}
		
}
}
package test;

public class Test4 {

	public static void main(String[] strs) {
		int k=0;
		for(int j=2;j<=100;j++)
		{
		int i;
		
            for(i=2;i<=Math.sqrt(j);i++)
			
			if(j%i==0)
			    break;
				
			if(i>Math.sqrt(j))
			{	
				k++;
				System.out.print(j+"   ");
				if(k==5)
				{
					System.out.println();
					k=0;
				}
			}
 }
}
}
package test;

import java.util.Scanner;

public class Test5 {
	public static void main(String[] args) {
		while(true){
			int sum=0,count=0;
			do{
			Scanner in=new Scanner(System.in);
		    int edg=in.nextInt();
			if(edg<0||edg>130)//判斷輸入
			{
				System.out.println("error");
				break;
			}
			else
			{
				count++;
				sum+=edg;
		    }
			}while(count<5);//輸入5次
		if(count==5){
			int avg;
			avg=sum/5;
		}
		
	}
	}
}
package test;

import java.util.Scanner;

public class Test6 {

	public static void main(String[] args) {
		System.out.println("請輸入高度：");
		Scanner sc=new Scanner(System.in);
		int h=sc.nextInt();
		for(int n=0;n<=h;n++)
		{
			for(int i=0;i<=h-n;i++)
				System.out.print(" ");
			for(int j=1;j<=2*n-1;j++)
				System.out.print("*");
			System.out.println();
		}
		
	}
}
package test;

public class Test7 {

	public static void main(String[] args) {
		System.out.println("公雞      "+"母雞        "+"小雞");
		for(int i=0;i<20;i++){//公雞個數
			for(int j=0;j<33;j++)//母雞個數
			{
				if((100-i-j)%3==0){//小雞是不是3的倍數
					if(i*5+j*3+(100-i-j)/3==100)
						System.out.println(i+"    "+j+"    "+(100-j-i));
				}
			}
		}
		
	}
}