JAVA for循环打印直角三角形
打印正直角三角形

	public static void main(String[] args) {
		//打印直角三角形1
		for (int i = 0; i < 5; i++) {
			for (int j = 0; j < i + 1; j++) {
				System.out.print("*");
			}
			System.out.println();
		}
	}



打印倒直角三角形
	public static void main(String[] args) {
		//打印直角三角形2
		for (int i = 0; i < 5; i++) {
			for (int j = 0; j < 5 - i; j++) {
				System.out.print("*");
			}
			System.out.println();
		}
	}
	



打印正直角三角形（反）
	public static void main(String[] args) {
		//打印直角三角形3
		for (int i = 0; i < 5; i++) {
			for (int j = 0; j < 5 - i; j++) {
				System.out.print(" ");
			}
			for (int j = 0; j < i + 1; j++) {
				System.out.print("*");
			}
			System.out.println();
		}
	}



打印倒直角三角形（反）
	public static void main(String[] args) {
		//打印直角三角形4
		for (int i = 0; i < 5; i++) {
			for (int j = 0; j < i + 1; j++) {
				System.out.print(" ");
			}
			for (int j = 0; j < 5 - i; j++) {
				System.out.print("*");
			}
			System.out.println();
		}
	}

一，java打印直角三角形

/**
 * for循环输出直角三角形
 */
public class Test16 {
    public static void main(String[] args) {
        for (int i=1;i<=9;i++){
            for (int j=1;j<=i;j++){
                System.out.print("*");
            }
            System.out.println();
        }
    }
}


执行代码如下：



二，java打印反过来的的直角三角形

/**
 * java打印反过来的的直角三角形
 */
public class Test17 {
    public static void main(String[] args) {
        for (int i=1;i<9;i++){
            for (int j=1;j<9-i;j++){
                System.out.print(" ");
            }
            for (int j=1;j<=i;j++){
                System.out.print("*");
            }
            System.out.println();
        }
    }
}


 

执行代码如下：

public class Test_s {
public void s1() {//正直角三角形
for (int i = 1; i <= 5; i++) {
for (int j = 1; j <= i; j++) {
System.out.print("*");
}System.out.println();
}
}
public void s2() {//倒直角三角形
for (int i = 1; i <=5; i++) {
for (int j = 1; j <= 6 - i; j++) {
System.out.print("*");
}System.out.println();
}
}
public void s3() {//正直角三角形水平翻转
for (int i = 1; i <=5; i++) {
for (int j = 1; j <= 5; j++) {
System.out.print(j > 5 - i ? "*":" ");
}System.out.println();
}
}
public void s4() {//倒正直角三角形水平翻转
for (int i = 1; i <=5; i++) {
for (int j = 1; j <= 5; j++) {
System.out.print(j >= i ? "*":" ");
}System.out.println();
}
}
public void s5() {//等腰三角形
int len = 7;
for (int i = 1; i <= 4; i++) {
for (int j = 1; j <= len; j++) {
System.out.print(j > len/2-i+1 && j <= len/2+i ? "*":" ");
}System.out.println();
}
}
public void s6() {//等腰三角形垂直翻转
int len = 13;
for (int i = 1; i <= 4; i++) {
for (int j = 1; j <= len; j++) {
System.out.print(j > (i - 1) * 2 && j < len + 3 - 2 * i ? "*" : " ");
}System.out.println();
}
}
public void s7() {//菱形
int height = 7;
for (int i = 1; i <= height; i++) {
for (int j = 1; j <= height; j++) {
if (i <= height / 2 + 1) {
System.out.print(j > height/2-i+1 && j <= height/2+i ? "*":" ");
} else {
System.out.print(j > i - height / 2 - 1 && j < height - i + height / 2 + 2 ? "*" : " ");
}
}
System.out.println();
}
}
public void s8() {//沙漏形
int height = 7;
for (int i = 1; i <= height; i++) {
for (int j = 1; j <= height; j++) {
if (i <= height / 2 + 1) {
System.out.print(j > i - 1 && j < height + 2 - i ? "*" : " ");
} else {
System.out.print(j > height-i && j < 1+i ? "*":" ");
}
}
System.out.println();
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
Test_s t_s = new Test_s();
t_s.s1();
System.out.println("-----------");
t_s.s2();
System.out.println("-----------");
t_s.s3();
System.out.println("-----------");
t_s.s4();
System.out.println("-----------");
t_s.s5();
System.out.println("-----------");
t_s.s6();
System.out.println("-----------");
t_s.s7();
System.out.println("-----------");
t_s.s8();
}
}

public class Test_s {
public void s1() {//正直角三角形
for (int i = 1; i <= 5; i++) {
for (int j = 1; j <= i; j++) {
System.out.print("*");
}System.out.println();
}
}
public void s2() {//倒直角三角形
for (int i = 1; i <=5; i++) {
for (int j = 1; j <= 6 - i; j++) {
System.out.print("*");
}System.out.println();
}
}
public void s3() {//正直角三角形水平翻转
for (int i = 1; i <=5; i++) {
for (int j = 1; j <= 5; j++) {
System.out.print(j > 5 - i ? "*":" ");
}System.out.println();
}
}
public void s4() {//倒正直角三角形水平翻转
for (int i = 1; i <=5; i++) {
for (int j = 1; j <= 5; j++) {
System.out.print(j >= i ? "*":" ");
}System.out.println();
}
}
public void s5() {//等腰三角形
int len = 7;
for (int i = 1; i <= 4; i++) {
for (int j = 1; j <= len; j++) {
System.out.print(j > len/2-i+1 && j <= len/2+i ? "*":" ");
}System.out.println();
}
}
public void s6() {//等腰三角形垂直翻转
int len = 13;
for (int i = 1; i <= 4; i++) {
for (int j = 1; j <= len; j++) {
System.out.print(j > (i - 1) * 2 && j < len + 3 - 2 * i ? "*" : " ");
}System.out.println();
}
}
public void s7() {//菱形
int height = 7;
for (int i = 1; i <= height; i++) {
for (int j = 1; j <= height; j++) {
if (i <= height / 2 + 1) {
System.out.print(j > height/2-i+1 && j <= height/2+i ? "*":" ");
} else {
System.out.print(j > i - height / 2 - 1 && j < height - i + height / 2 + 2 ? "*" : " ");
}
}
System.out.println();
}
}
public void s8() {//沙漏形
int height = 7;
for (int i = 1; i <= height; i++) {
for (int j = 1; j <= height; j++) {
if (i <= height / 2 + 1) {
System.out.print(j > i - 1 && j < height + 2 - i ? "*" : " ");
} else {
System.out.print(j > height-i && j < 1+i ? "*":" ");
}
}
System.out.println();
}
}
public static void main(String[] args) {
// TODO Auto-generated method stub
Test_s t_s = new Test_s();
t_s.s1();
System.out.println("-----------");
t_s.s2();
System.out.println("-----------");
t_s.s3();
System.out.println("-----------");
t_s.s4();
System.out.println("-----------");
t_s.s5();
System.out.println("-----------");
t_s.s6();
System.out.println("-----------");
t_s.s7();
System.out.println("-----------");
t_s.s8();
}
}