n |---- If there are 4 students in 3 classes, how to calculate the average score of the participating students in each class?
|-----No array, use 3 variables + multiple loops (multiplication)
|---- print a simple rectangle
publicstaticvoid main(String[] args) { // TODO Auto-generated method stub for(int i=1;i<=5;i++){ // number of lines for(int j=1;j<=20;j++){ System.out.print("*"); } System.out.println();//换行 } } |
|---- print right triangle
publicstaticvoid main(String[] args) { // TODO Auto-generated method stub Scanner sc= new Scanner(System. in ); // Scanner System.out .println ( " Please enter the number of triangle lines: " ); int rows=sc.nextInt(); for(int i=1;i<=rows;i++){ // number of lines to print // The * number displayed in each line , regular for(int j=1;j<=2*i-1;j++){ System.out.print("*"); } System.out.println(); } } |
|----Field Programming: Inverted Right Triangle
|----Rule: One less per line!
publicstaticvoid main(String[] args) { // TODO Auto-generated method stub Scanner sc=new Scanner(System.in); System . out .println( " Please enter the number of lines: " ); int rows=sc.nextInt(); for(int i=1;i<=rows;i++){ // number of lines for(int j=1;j<=rows-i+1;j++){ System.out.print("*"); } System.out.println(); } } |
|------打印等腰三角形
|-----1:占位置 2:1,3,5,7
publicstaticvoid main(String[] args) { // TODO Auto-generated method stub Scanner sc=new Scanner(System.in); System.out.println("请输入等腰三角形的行数:"); int rows=sc.nextInt(); for(int i=1;i<=rows;i++){ //占位 倒直角三角形 规律 for(int j=1;j<=rows-i;j++){ System.out.print(" "); } for(int k=1;k<=2*i-1;k++){ if(k==1||k==2*i-1){ System.out.print("*"); }else{ System.out.print(" "); } } System.out.println(); } } |
|---打印九九乘法表
publicstaticvoid main(String[] args) { // TODO Auto-generated method stub for(int i=1;i<=9;i++){ //行数 for(int j=1;j<=i;j++){ System.out.print(i+"X"+j+"="+(i*j)+"\t"); } System.out.println();//换行 } } |
|-----结合等腰和九九乘法表 试着打印一个菱形,不能输入偶数?17 7 把菱形进行缕空?
|------分成上部份和下部份
publicstaticvoid main(String[] args) { // TODO Auto-generated method stub Scanner sc=new Scanner(System.in); System.out.println("请输入菱形的行数:"); int rows=sc.nextInt(); while(rows%2==0){ System.out.println("请输入菱形的行数:"); rows=sc.nextInt(); } //拆分成两部份 //打印上部份 int uprow=(rows+1)/2; for(int i=1;i<=uprow;i++){ //占位 for(int j=1;j<=uprow-i;j++){ System.out.print(" "); } for(int k=1;k<=2*i-1;k++){ //System.out.print("*"); if(k==1||k==2*i-1){ System.out.print("*"); }else{ System.out.print(" "); } } System.out.println(); } //打印下部份 int downrow=rows-uprow; for(int i=downrow;i>=1;i--){ //占位 for(int j=1;j<=downrow-i+1;j++){ System.out.print(" "); } for(int k=1;k<=2*i-1;k++){ if(k==1||k==2*i-1){ System.out.print("*"); }else{ System.out.print(" "); } } System.out.println(); } } |
n |-----使用continue统计大于85分的学员人数
|-----break用在多循环中
n |----有5家衣服专卖店,每家最多购买3件。用户可以选择离开,可以买衣服
n 最后打印总共买了几件衣服 用break来实现?
|---1:外层循环有5次
|---2:内层控制3次 用户可以选择离开(break),可以买衣服
|----3:最后再统计买了多少件衣服?
for(){do{}while();}
publicstaticvoid main(String[] args) { // TODO Auto-generated method stub Scanner sc=new Scanner(System.in); int count=0; String flag="n";//标志位 for(int i=0;i<5;i++){ System.out.println("欢迎进入第"+(i+1)+"家专卖店:"); do{ System.out.println("要离开吗?(y/n)"); flag=sc.next(); if(flag.equals("y")){ break; } System.out.println("买一件衣服!"); count++; }while(flag.equals("n")); } System.out.println("总共买了"+count+"件衣服!"); }
|
publicstaticvoid main(String[] args) { // TODO Auto-generated method stub Scanner sc=new Scanner(System.in); int count=0; int sum=0; String flag="n";//标志位 for(int i=0;i<5;i++){ count=0;//i执行1次,那么count清零 System.out.println("欢迎进入第"+(i+1)+"家专卖店:"); do{ System.out.println("要离开吗?(y/n)"); flag=sc.next(); if(flag.equals("y")){ sum+=count; break;//输入y退出 } System.out.println("买一件衣服!"); count++; if(count>=3){ sum+=count; break; } }while(flag.equals("n")); } System.out.println("总共买了"+sum+"件衣服!"); } |