java 打印星号

代码1

package lesson.l2_for;
//6列4行
//******
//******
//******
//******
public class ForDemo8 {public static void main(String[] args) {for (int i=1;i<=4;i++){for (int j = 1; j <=6 ; j++) {System.out.print("*");}System.out.println();}}
}

代码2

package lesson.l2_for;
//打印
//*
//**
//***
//****
//*****
public class ForDemo9 {public static void main(String[] args) {for (int i = 1; i <= 5; i++) {for (int j = 1; j <= i; j++) {System.out.print("*");}System.out.println();}}
}

代码2-1

package lesson.l2_for;
//打印
//****
//***
//**
//*
public class ForDemo10 {public static void main(String[] args) {for (int i = 4; i >= 1; i--) {for (int j = i; j >= 1; j--) {System.out.print("*");}System.out.println();}}
}

代码2-2

package lesson.l2_for;
//打印
//****
//***
//**
//*
public class ForDemo10_2 {public static void main(String[] args) {for (int i = 1; i <=4 ; i++) {for (int j = 1; j <=5-i ; j++) {System.out.print("*");}System.out.println();}}
}

代码3

package lesson.l2_for;
//打印
//*
//**
//***
//****
//*****
//****
//***
//**
//*
public class ForDemo11 {public static void main(String[] args) {for (int i = 1; i <= 5; i++) {for (int j = 1; j <= i; j++) {System.out.print("*");}System.out.println();}for (int i = 1; i <= 4; i++) {for (int k = 1; k <= 5 - i; k++) {System.out.print("*");}System.out.println();}}
}

代码4

在这里插入图片描述

package lesson.l2_for;//打印棱形public class ForDemo12 {public static void main(String[] args) {for (int i = 1; i <= 5; i++) {for (int j = 1; j <=6-i; j++) {System.out.print(" ");}for (int k = 1; k <= i; k++) {System.out.print(" *");}System.out.println();}for (int i = 1; i <=4 ; i++) {for (int j = 1; j <=i+1 ; j++) {System.out.print(" ");}//for (int j = i; j <=4; j++) {for (int j = 1; j <=5-i; j++) {System.out.print(" *");}System.out.println();}}
}

代码5

在这里插入图片描述

package lesson.l2_for;
//打印
//        **********
//        ****  ****
//        ***    ***
//        **      **
//        *        *
//        **      **
//        ***    ***
//        ****  ****
//        **********
public class ForDemo13 {public static void main(String[] args) {//上半部分for (int i = 1; i <= 5; i++) {for (int j = 1; j <= 6 - i; j++) {System.out.print("*");}for (int j = 1; j <= i - 1; j++) {System.out.print("  ");}for (int j = 1; j <= 6 - i; j++) {System.out.print("*");}System.out.println();}//下半部分for (int i = 2; i <= 5; i++) {for (int j = 1; j <= i; j++) {System.out.print("*");}for (int j = 1; j <= 5 - i; j++) {System.out.print("  ");}for (int j = 1; j <= i; j++) {System.out.print("*");}System.out.println();}}
}