双重for循环的几个例子

打印直角三角形

for(int x=1;x<=4;x++){    for(int y=1;y<=x;y++){System.out.print("*");    }    System.out.println();}

打印等腰三角形

for (int x = 1;x<=5 ;x++ ){     for (int i = x;i<=4;i++ ){         System.out.print(" ");     }     for (int y =1;y<=x ;y++ ){         System.out.print("*"+" ");     }     System.out.println();}System.out.println("---------------");for(int i = 1;i<=5;i++){    for (int j = 0;j<=i-1 ;j++ ){         System.out.print(" ");    }    for (int k = 5;k>=i ;k-- ){         System.out.print("*"+" ");    }    System.out.println();}

九九乘法

for(int x=1;x<=9;x++){    for(int y=1;y<=x;y++){System.out.print(y+"×"+x+"="+y*x+"\t");    }    System.out.println();}