本作者是基於Eclipse編寫的程序，當然也可以用TextPad或NetBeans進行編程。不管用哪一種，學習的重點都是將具體問題轉化成程序化語言的能力，學習的是這種思想。希望童鞋們和我一樣，每天進步一點點！廢話少說，進入正題
示例一：用戶輸入某一年，程序輸出顯示這一年每個月的日曆。(你能自己設計出來嗎？)請看運行效果圖（只展示了前六月的六張圖）。
這道題目有幾個坑：
1)如何顯示對齊以符合要求；
2)如何確定每月第一天是星期幾；
3)如何判斷某一月有多少天；
4)閏年的情況要考慮周到。
基於Eclipse的實現代碼如下：
package shiyanPractice;
import java.util.Scanner;
public class ShiYanPractice {
public static void main(String[] args) {
//輸入年份，顯示相應年份的日曆
Scanner input = new Scanner(System.in);
System.out.print("Enter the number of year: ");
int year = input.nextInt();//輸入想要顯示的年份
int month = 1;
int day = 0;
//12個月，所以循環12次，每次顯示一個月的日曆
for(int i = 0;i < 12;i++){
int h,q,m,j,k;
month = i+1;
day = 1; //只需算出每個月的第一天是周幾
m = month;
q = day;
//當月份爲1或2時，要將其視爲上一年的13或14月，並且相應的年份改爲上一年
if(m == 1 || m == 2){
m+=12;
year -= 1;
}
j = year/100; //求出h表示的星期幾，其中0表示週日，1表示週六，2表示週一，直到6表示週五
k = year%100;
//澤勒一致性公式
h = (q+(int)(26*(m+1)/10)+k+(int)(k/4)+(int)(j/4)+5*j)%7;
//計算完h之後要將year的值改回來
if(month == 1 ||month == 2)
year += 1;
//用於將h轉換成對應的星期幾
String dayTranslate = "";
switch(h){
case 0:dayTranslate = "Saturday";break;
case 1:dayTranslate = "Sunday";break;
case 2:dayTranslate = "Monday";break;
case 3:dayTranslate = "Thusday";break;
case 4:dayTranslate = "Wednesday";break;
case 5:dayTranslate = "Thursday";break;
case 6:dayTranslate = "Friday";break;
}
//用以顯示日曆的每個月的擡頭
String monthFor = "";
switch(month){
case 1:monthFor = "January";break;
case 2:monthFor = "February";break;
case 3:monthFor = "March";break;
case 4:monthFor = "April";break;
case 5:monthFor = "May ";break;
case 6:monthFor = "June ";break;
case 7:monthFor = "July ";break;
case 8:monthFor = "August";break;
case 9:monthFor = "September";break;
case 10:monthFor = "October";break;
case 11:monthFor = "November";break;
case 12:monthFor = "December";break;
}
//顯示每個月的擡頭
String title = "\t"+monthFor+" "+year+"\n"
+"Sun "+"Mon "+"Tue "+"Wed "+"Thu "+"Fri "+"Sat\n";
System.out.println(title);
//將h轉換成相應的星期幾的數字
int dayCount = 0;
switch(h){
case 0:dayCount = 6;break;
case 1:dayCount = 0;break;
case 2:dayCount = 1;break;
case 3:dayCount = 2;break;
case 4:dayCount = 3;break;
case 5:dayCount = 4;break;
case 6:dayCount = 5;break;
}
//某個月第一天在日曆中位置的確認
for(int jj = 1;jj <= dayCount;jj++){
System.out.print(" ");
}
int countToAnotherLine = dayCount+1;//將第一天的位置數加1，方便用於後續轉行的控制
//計算每個月的天數
int countDayPerMonth = 31;
switch(month){
case 1:countDayPerMonth = 31;break;
case 2:
if((year % 4 == 0 && year % 100 != 0)||(year % 400 ==0))
countDayPerMonth = 29;
else
countDayPerMonth = 28;
break;
case 3:countDayPerMonth = 31;break;
case 4:countDayPerMonth = 30;break;
case 5:countDayPerMonth = 31;break;
case 6:countDayPerMonth = 30;break;
case 7:countDayPerMonth = 31;break;
case 8:countDayPerMonth = 31;break;
case 9:countDayPerMonth = 30;break;
case 10:countDayPerMonth = 31;break;
case 11:countDayPerMonth = 30;break;
case 12:countDayPerMonth = 31;break;
}
//依次輸出某個月的每一天
for(int ii = 1;ii <= countDayPerMonth;ii++){
if(countToAnotherLine % 7 == 0){
System.out.printf("%3d ",ii);
System.out.println();
countToAnotherLine++;
}
else{
System.out.printf("%3d ",ii);
countToAnotherLine++;
}
}
System.out.println();
}
}
}
此題的坑在“連續”兩字上，要處理好交替贏和中間有平局的情況。下面是實現代碼：
package shiyanPractice;
import java.util.Scanner;
public class ShiYanPractice {
public static void main(String[] args) {
//石頭剪子布的遊戲，電腦或用戶贏兩次以上就獲勝，遊戲結束
Scanner input = new Scanner(System.in);
int pc_user_Win = 0;//1 userwin,2 pcwin
int pc_user_WinLastTime = 0;
int pcData = 0;
int userData = 0;
System.out.println("石頭、剪子、布遊戲，由用戶和電腦玩，誰連續贏兩次就勝出！");
while(true){
pcData = (int)(Math.random()*3+1);
System.out.print("玩家請輸入，1是剪刀，2是石頭，3是布:");
userData = input.nextInt();
//統計誰贏，並將pc_user_Win標誌位賦值，輸出顯示贏家
switch(userData){
case 1:{
if(userData - pcData == -2){
pc_user_Win = 1;
System.out.println("User Win!");
break;
}
else if(userData - pcData == -1){
pc_user_Win = 2;
System.out.println("Pc Win!");
break;
}
else{
System.out.println("User and Pc is same!");
break;
}
}
case 2:{
if(userData - pcData == 1){
pc_user_Win = 1;
System.out.println("User Win!");
break;
}
else if(userData - pcData == -1){
pc_user_Win = 2;
System.out.println("Pc Win!");
break;
}
else{
System.out.println("User and Pc is same!");
break;
}
}
case 3:{
if(userData - pcData == 1){
pc_user_Win = 1;
System.out.println("User Win!");
break;
}
else if(userData - pcData == 2){
pc_user_Win = 2;
System.out.println("Pc Win!");
break;
}
else{
System.out.println("User and Pc is same!");
break;
}
}
}
//判斷是否連續贏兩次，是就輸出誰贏，並結束循環
if(pc_user_Win != 0){//排除因爲等於零的情況的誤判，因爲等於零代表沒有勝負
if(pc_user_WinLastTime == pc_user_Win && pc_user_Win == 1){
System.out.println("User Win the game!");
break;
}
else if(pc_user_WinLastTime == pc_user_Win && pc_user_Win == 2){
System.out.println("Pc Win the game!");
break;
}
}
//只有將非零的勝負標誌值賦值給記錄上一次勝負情況的標誌位
//否則可能出現pc贏一次，平一次，再贏一次而不顯示pc獲勝的情況
if(pc_user_Win == 0);
else
pc_user_WinLastTime = pc_user_Win;
pc_user_Win = 0;//將標誌位置爲無效，否則將影響下一次判斷
}
}
}
此題相對來說比較容易，但還是得自己動手實踐，實踐可以檢查自己的問題並提高自我。運行效果圖如下：
package shiyanPractice;
import java.util.Scanner;
public class ShiYanPractice {
public static void main(String[] args) {
//找出完全數的程序
Scanner input = new Scanner(System.in);
System.out.print("Enter an integer: ");
int data = input.nextInt();
System.out.println(0+"~"+data+"之間的完全數顯示如下：");
for(int iData = 0;iData < data;iData++){
int number = 2;
int sumOfNumber = 1;
while(number <= iData){
if(iData % number == 0){
if(number != iData)
sumOfNumber += number;
number++;
}
else
number++;
}
if(iData == sumOfNumber &&iData != 1){
System.out.println(iData);
}
}
}
}
運行效果如圖所示：
實現代碼如下所示：
package shiyanPractice;
import java.util.Scanner;
public class ShiYanPractice {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("輸入需要輸入整型數的次數： ");
int n = input.nextInt();
for(int i = 0;i < n; i++){
System.out.print("Enter an integer: ");
int value = input.nextInt();
System.out.print("The 16 bits are: ");
int mask = 1;
for(int j = 15;j >=0; j--){
int temp = value>>j;
int bit = temp & mask;
System.out.print(bit);
}
System.out.println();
}
}
}