练习题

循环输出 * * * * * * * * * * | | | | public class Tree{ public static void main (String [] args){ int line = 4; int i; int j; for(i=0;i<line;i++){ for(j=0;j<line-i;j++){ System.out.print(" “); } for(j = 0;j<i+1;j++){ System.out.print(”* “); } System.out.println(); } for(i=0;i<2;i++){ for(j=0;j<line-1;j++){ System.out.print(” “); } for(j = 0;j<2;j++){ System.out.print(”| "); } System.out.println(); } } }输出 99乘法口诀表 11=1 12=2 2*2=4 …

public class Chengfabiao{ public static void main(String[] args){ int i; int j; for(i=1;i<10;i++){ for(j=1;j<=i;j++){ System.out.print(j+""+i+"="+ij+"\t"); } System.out.println(); } } }

鸡兔同笼（输入头和脚的数量，输出鸡和兔的个数） import java.util.; public class Jitu{ public static void main(String[] args){ Scanner scanner =new Scanner (System.in); int heads=scanner.nextInt(); int feet=scanner.nextInt(); int c=(feet-2heads)/2; int t=heads-(feet-2*heads)/2; if (feet%2!=0||c<0||t<0){ System.out.println(“0”); }else{ System.out.println(“c=”+c); System.out.println(“t=”+t); } } }