选择
BDCDA CABCC
程序填空
5-1
str.toCharArray()
i<x.length
ch>='a'&&ch<='z' ||ch>='A'&&ch<='Z'
ch>='0'&&ch<='9'
c++
5-2
sc.nextLine()
str.charAt(i)
String.valueOf(curChar).toUpperCase()
String.valueOf(curChar).toLowerCase()
sb.append(s1)
sb.toString()
5-3
super(a);
this.a=super.a*10;
super.a
this.a
编程题
7-1
import java.util.Scanner;
class Rectangle {
double width = 1;
double height = 1;
Rectangle() {
}
Rectangle(double width, double height) {
this.width = width;
this.height = height;
}
double getArea() {
return width * height;
}
double getPerimeter() {
return 2 * (width + height);
}
}
class Main{
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
double width = scanner.nextDouble();
double height = scanner.nextDouble();
Rectangle rectangle1 = new Rectangle(width, height);
System.out.println(rectangle1.width + " " + rectangle1.height + " " + rectangle1.getArea() + " " + rectangle1.getPerimeter());
width = scanner.nextDouble();
height = scanner.nextDouble();
Rectangle rectangle2 = new Rectangle(width, height);
System.out.print(rectangle2.width + " " + rectangle2.height + " " + rectangle2.getArea() + " " + rectangle2.getPerimeter());
}
}
7-2
import java.util.Scanner;
interface ICompute{
int computer(int n, int m);
}
class Add implements ICompute{
public int computer(int n, int m){
return n+m;
}
}
class Sub implements ICompute{
public int computer(int n, int m){
return n-m;
}
}
class Main{
public static void main(String[] args){
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
int b = sc.nextInt();
ICompute add = new Add();
ICompute sub = new Sub();
System.out.println(add.computer(a, b));
System.out.println(sub.computer(a, b));
}
}
7-3
import java.util.Scanner;
class Circle{
private double radius;
Circle(double radius){
this.radius = radius;
}
Circle(){
this.radius =0;
}
void setRadius(double r){
this.radius = r;
}
double getRadius(){
return this.radius;
}
double getArea(){
return Math.PI * this.radius * this.radius;
}
double getPerimeter(){
return Math.PI * this.radius * 2;
}
public String toString(){
return"Circle(r:"+this.radius+")";
}
}
class Cylinder{
private double height;
private Circle circle;
Cylinder(double height,Circle circle){
this.height = height;
this.circle = circle;
}
Cylinder(){
this.height = 0;
this.circle = new Circle();
}
void setHeight(double height){
this.height = height;
}
double getHeight(){
return this.height;
}
void setCircle(Circle circle){
this.circle = circle;
}
Circle getCircle(){
return this.circle;
}
double getArea(){
return 2 * this.circle.getArea() + this.circle.getPerimeter() * this.height;
}
double getVolume(){
return this.circle.getArea() * this.height;
}
public String toString(){
return "Cylinder(h:"+this.height+","+this.circle+")";
}
}
public class Main{
public static void main(String args[]) {
Scanner input = new Scanner(System.in);
int n = input.nextInt();
for(int i = 0; i < n; i++) {
String str = input.next();
if(str.equals("Circle")) {
Circle c = new Circle(input.nextDouble());
System.out.println("The area of " + c.toString() + " is " + String.format("%.2f",c.getArea()));
System.out.println("The perimeterof " + c.toString() + " is "+ String.format("%.2f",c.getPerimeter()));
} else if(str.equals("Cylinder")) {
Cylinder r = new Cylinder(input.nextDouble(), new Circle(input.nextDouble()));
System.out.println("The area of " + r.toString() + " is " + String.format("%.2f",r.getArea()));
System.out.println("The volume of " + r.toString() + " is " + String.format("%.2f",r.getVolume()));
}
}
}
}
7-4
import java.util.Scanner;
class Shape{
double PI=3.1415926;
public double area(){
return 0;
}
public double perimeter(){
return 0;
}
}
class Oval extends Shape{
private double a;
private double b;
public Oval(double a,double b){
this.a=a;
this.b=b;
}
public Oval(){
this.a=0;
this.b=0;
}
public double area(){
return PI*a*b;
}
public double perimeter(){
return 2*PI*Math.sqrt((a*a+b*b)/2);
}
public String toString(){
return "Oval(a:"+a+",b:"+b+")";
}
}
public class Main {
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
double a=sc.nextDouble();
double b=sc.nextDouble();
Oval o=new Oval(a,b);
System.out.println("The area of "+o.toString()+" is "+o.area());
System.out.println("The perimeterof "+o.toString()+" is "+o.perimeter());
}
}
7-5
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
String statement;
Scanner sc =new Scanner(System.in);
statement=sc.nextLine();
String word1=sc.next();
String word2=sc.next();//用word2替换word1
String words[]=statement.split(" ");
/* for(int i=0;i<words.length;i++)
System.out.print(words[i]+"\t");*/
for(int i=0;i<words.length;i++) {//将句子分割成单词
if(word1.equals(words[i])) {
words[i]=word2;
}
}
StringBuffer stb=new StringBuffer();
String sta=null;
for(int i=0;i<words.length;i++) {//数组转换为句子
if(i==words.length-1)stb.append(words[i]);
else stb.append(words[i]+" ");
}
sta=stb.toString();
System.out.println(sta);
sc.close();
}
}
7-6
import java.util.Scanner;
interface Shape{
double length();
}
class Triangle implements Shape{
double a;
double b;
double c;
Triangle(){
this.a = this.b = this.c = 0;
}
Triangle(double a){
this.a = this.b = this.c = 0;
}
Triangle(double a, double b){
this.a = this.b = this.c = 0;
}
Triangle(double a, double b, double c){
this.a = a;
this.b = b;
this.c = c;
if(a <= 0 || b <= 0 || c <= 0 || !(a + b > c && a + c > b && b + c > a)){
this.a = this.b = this.c = 0;
}
}
@Override
public double length() {
return a + b + c;
}
}
class Rectangle implements Shape{
double a, b;
Rectangle(){
this.a = this.b = 0;
}
Rectangle(double a){
this.a = this.b = 0;
}
Rectangle(double a, double b){
this.a = a;
this.b = b;
if(a <= 0 || b <= 0){
this.a = this.b = 0;
}
}
@Override
public double length() {
return 2 * (a + b);
}
}
class Circle implements Shape{
double r;
Circle(){
r = 0;
}
Circle(double r){
this.r = r;
if(r <= 0) this.r = 0;
}
@Override
public double length() {
return 2 * 3.14 * r;
}
}
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
while(sc.hasNextInt()) {
double[] l = new double[5];
String s;
s = sc.nextLine();
String[] str = s.split(" ");
int cnt = 0;
for (String value : str) {
l[cnt++] = Double.parseDouble(value);
}
if(cnt == 1){
Circle C = new Circle(l[0]);
System.out.printf("%.2f\n", C.length());
}
else if (cnt == 2){
Rectangle r = new Rectangle(l[0], l[1]);
System.out.printf("%.2f\n", r.length());
}
else{
Triangle t = new Triangle(l[0], l[1], l[2]);
System.out.printf("%.2f\n", t.length());
}
}
}
}
