Java範例程式 : 氣泡排序學生成績

以下採用三種不同的氣泡排序將學生成績由高至低排好.
方法一 內層迴圈所指位置與外層迴圈比大小(都是由左至右比較)
程式碼

import java.io.*;

class C7P155
{
 public static void main(String[] args) throws IOException
 {
  int student_num = 0, maxgr = 0, mingr = 0, maxid = 0, minid = 0, sum = 0, ccount = 0, scount = 0;
  boolean status = false;
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

  System.out.println("學生成績分析程式 ");
  do{
   System.out.print("請輸入學生人數 ");
   try{
    student_num = Integer.parseInt(br.readLine());
    status = false;
   } catch ( NegativeArraySizeException e ){
    System.out.println("請輸入正整數的學生人數.");
    status = true;
   } catch ( NumberFormatException e ){
    System.out.println("請輸入學生人數.");
    status = true;
   }
  } while (status);

  int grade[] = new int[student_num];

  System.out.println("\n開始輸入學生成績");

  for(int i = 0; i < student_num; i++){
   status = false;
   do{
    System.out.print("學生 " + (i+1) + " 成績 ");
    try{
     grade[i] = Integer.parseInt(br.readLine());
     sum += grade[i];
     if( i == 0 ){
      maxgr = mingr = grade[i];
     }else{
      if(grade[i] > maxgr){
       maxgr = grade[i]; maxid = i;
      } else if(grade[i] < mingr){
       mingr = grade[i]; minid = i;
      }
     }
     status = false;
    } catch ( NumberFormatException e ){
     System.out.println("請輸入正整數的成績.");
     status = true;
    }
   } while (status);
  }

  System.out.println("\n開始輸出學生成績");
  for(int i = 0; i < grade.length; i++){
   System.out.println("學生 " + (i+1) + " 成績 " + grade[i]);
  }
  System.out.println("\n最高最低成績");
  System.out.println("最高成績 第 " + (maxid+1) + " 號學生成績" + grade[maxid]);
  System.out.println("最低成績 第 " + (minid+1) + " 號學生成績" + grade[minid]);

  System.out.println("\n平均成績 " + (float)sum/(float)grade.length);

  System.out.println("\n成績排行榜");
  // Generate student id array
  int stid[] = new int[grade.length];
  for(int i = 0; i < grade.length; i++){ stid[i] = i; }

  // Sort by grade via bubble sort
  System.out.print("成績排序中 ");
  for(int i = 0; i < (grade.length - 1); i++){
   for(int j = i+1; j < grade.length; j++){
    if(grade[j] > grade[i]){
     // swap
     int tmpgr = grade[j];
     int tmpid = stid[j];
     grade[j] = grade[i];
     stid[j] = stid[i];
     grade[i] = tmpgr;
     stid[i] = tmpid;
     scount++;
     System.out.print("s");
    } else {
     System.out.print(".");
    }
    ccount++;
   }
  }
  System.out.println("\nSwap / Total comparison : " + scount + " / " + ccount);

  System.out.println("\n成績排序結果");
  int rank = 1;
  for(int i = 0; i < grade.length; i++){
   if( i != 0 && grade[i] != grade[i-1] ){ rank++; }
   System.out.println("名次 " + (i+1) + " 第 " + (stid[i]+1) + " 號學生成績 " + grade[i]);
  }
 }
}

物件導向版

import java.io.*;

class Student
{
 int sid;
 int grade;

 public void setGrade(int sid, int grade)
 {
  this.sid = sid;
  this.grade = grade;
 }

 public int getGrade()
 {
  return this.grade;
 }

 public int getSid()
 {
  return this.sid;
 }
}

class C8P158
{
 public static void main(String[] args) throws IOException
 {
  int student_num = 0, maxgr = 0, mingr = 0, maxid = 0, minid = 0, sum = 0, ccount = 0, scount = 0;
  boolean status = false;
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

  System.out.println("學生成績分析程式 ");
  do{
   System.out.print("請輸入學生人數 ");
   try{
    student_num = Integer.parseInt(br.readLine());
    status = false;
   } catch ( NegativeArraySizeException e ){
    System.out.println("請輸入正整數的學生人數.");
    status = true;
   } catch ( NumberFormatException e ){
    System.out.println("請輸入學生人數.");
    status = true;
   }
  } while (status);

  Student grade[] = new Student[student_num];

  System.out.println("\n開始輸入學生成績");

  for(int i = 0; i < student_num; i++){
   status = false;
   int tmpgrade = 0;
   do{
    System.out.print("學生 " + (i+1) + " 成績 ");
    try{
     tmpgrade = Integer.parseInt(br.readLine());
     grade[i] = new Student();
     grade[i].setGrade( i + 1, tmpgrade );
     sum += grade[i].getGrade();
     if( i == 0 ){
      maxgr = mingr = grade[i].getGrade();
     }else{
      if(grade[i].getGrade() > maxgr){
       maxgr = grade[i].getGrade(); maxid = i;
      } else if(grade[i].getGrade() < mingr){
       mingr = grade[i].getGrade(); minid = i;
      }
     }
     status = false;
    } catch ( NumberFormatException e ){
     System.out.println("請輸入正整數的成績.");
     status = true;
    }
   } while (status);
  }

  System.out.println("\n開始輸出學生成績");
  for(int i = 0; i < grade.length; i++){
   System.out.println("學生 " + (grade[i].getSid()) + " 成績 " + grade[i].getGrade());
  }
  System.out.println("\n最高最低成績");
  System.out.println("最高成績 第 " + grade[maxid].getSid() + " 號學生成績" + grade[maxid].getGrade());
  System.out.println("最低成績 第 " + grade[minid].getSid() + " 號學生成績" + grade[minid].getGrade());

  System.out.println("\n平均成績 " + (float)sum/(float)grade.length);

  System.out.println("\n成績排行榜");
  // Sort by grade via bubble sort
  System.out.print("成績排序中 ");
  for(int i = 0; i < (grade.length - 1); i++){
   for(int j = i+1; j < grade.length; j++){
    if(grade[j].getGrade() > grade[i].getGrade()){
     // swap
     Student tmpgr = grade[j];
     grade[j] = grade[i];
     grade[i] = tmpgr;
     scount++;
     System.out.print("s");
    } else {
     System.out.print(".");
    }
    ccount++;
   }
  }
  System.out.println("\nSwap / Total comparison : " + scount + " / " + ccount);

  System.out.println("\n成績排序結果");
  int rank = 1;
  for(int i = 0; i < grade.length; i++){
   if( i != 0 && grade[i].getGrade() != grade[i-1].getGrade() ){ rank++; }
   System.out.println("名次 " + (rank) + " 第 " + grade[i].getSid() + " 號學生成績 " + grade[i].getGrade());
  }
 }
}

方法二 外層迴圈由右至左, 為限制內層迴圈比較的右邊界. 內層迴圈迴圈由左至右, 相近位置兩兩比較大小.
程式碼

import java.io.*;

class C7P155_1
{
 public static void main(String[] args) throws IOException
 {
  int student_num = 0, maxgr = 0, mingr = 0, maxid = 0, minid = 0, sum = 0, scount = 0, ccount = 0;
  boolean status = false;
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

  System.out.println("學生成績分析程式 ");
  do{
   System.out.print("請輸入學生人數 ");
   try{
    student_num = Integer.parseInt(br.readLine());
    status = false;
   } catch ( NegativeArraySizeException e ){
    System.out.println("請輸入正整數的學生人數.");
    status = true;
   } catch ( NumberFormatException e ){
    System.out.println("請輸入學生人數.");
    status = true;
   }
  } while (status);

  int grade[] = new int[student_num];

  System.out.println("\n開始輸入學生成績");

  for(int i = 0; i < student_num; i++){
   status = false;
   do{
    System.out.print("學生 " + (i+1) + " 成績 ");
    try{
     grade[i] = Integer.parseInt(br.readLine());
     sum += grade[i];
     if( i == 0 ){
      maxgr = mingr = grade[i];
     }else{
      if(grade[i] > maxgr){
       maxgr = grade[i]; maxid = i;
      } else if(grade[i] < mingr){
       mingr = grade[i]; minid = i;
      }
     }
     status = false;
    } catch ( NumberFormatException e ){
     System.out.println("請輸入正整數的成績.");
     status = true;
    }
   } while (status);
  }

  System.out.println("\n開始輸出學生成績");
  for(int i = 0; i < grade.length; i++){
   System.out.println("學生 " + (i+1) + " 成績 " + grade[i]);
  }
  System.out.println("\n最高最低成績");
  System.out.println("最高成績 第 " + (maxid+1) + " 號學生成績" + grade[maxid]);
  System.out.println("最低成績 第 " + (minid+1) + " 號學生成績" + grade[minid]);

  System.out.println("\n平均成績 " + (float)sum/(float)grade.length);

  System.out.println("\n成績排行榜");
  // Generate student id array
  int stid[] = new int[grade.length];
  for(int i = 0; i < grade.length; i++){ stid[i] = i; }

  // Sort by grade via bubble sort
  System.out.print("成績排序中 ");
  for(int i = grade.length - 1; i > 0; i--){
   for(int j = 0; j < i; j++){
    if(grade[j+1] > grade[j]){
     // swap
     int tmpgr = grade[j+1];
     int tmpid = stid[j+1];
     grade[j+1] = grade[j];
     stid[j+1] = stid[j];
     grade[j] = tmpgr;
     stid[j] = tmpid;
     scount++;
     System.out.print("s");
    } else {
     System.out.print(".");
    }
    ccount++;
   }
  }
  System.out.println("\nSwap / Total comparison : " + scount + " / " + ccount);

  System.out.println("\n成績排序結果");
  int rank = 1;
  for(int i = 0; i < grade.length; i++){
   if( i != 0 && grade[i] != grade[i-1] ){ rank++; }
   System.out.println("名次 " + (rank) + " 第 " + (stid[i]+1) + " 號學生成績 " + grade[i]);
  }
 }
}

物件導向版

import java.io.*;

class Student
{
 int sid;
 int grade;

 public void setGrade(int sid, int grade)
 {
  this.sid = sid;
  this.grade = grade;
 }

 public int getGrade()
 {
  return this.grade;
 }

 public int getSid()
 {
  return this.sid;
 }
}

class C8P158_1
{
 public static void main(String[] args) throws IOException
 {
  int student_num = 0, maxgr = 0, mingr = 0, maxid = 0, minid = 0, sum = 0, scount = 0, ccount = 0;
  boolean status = false;
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

  System.out.println("學生成績分析程式 ");
  do{
   System.out.print("請輸入學生人數 ");
   try{
    student_num = Integer.parseInt(br.readLine());
    status = false;
   } catch ( NegativeArraySizeException e ){
    System.out.println("請輸入正整數的學生人數.");
    status = true;
   } catch ( NumberFormatException e ){
    System.out.println("請輸入學生人數.");
    status = true;
   }
  } while (status);

  Student grade[] = new Student[student_num];

  System.out.println("\n開始輸入學生成績");

  for(int i = 0; i < student_num; i++){
   status = false;
   do{
    System.out.print("學生 " + (i+1) + " 成績 ");
    try{
     grade[i] = new Student();
     grade[i].setGrade( i + 1, Integer.parseInt(br.readLine()) );
     sum += grade[i].getGrade();
     if( i == 0 ){
      maxgr = mingr = grade[i].getGrade();
     }else{
      if(grade[i].getGrade() > maxgr){
       maxgr = grade[i].getGrade(); maxid = i;
      } else if(grade[i].getGrade() < mingr){
       mingr = grade[i].getGrade(); minid = i;
      }
     }
     status = false;
    } catch ( NumberFormatException e ){
     System.out.println("請輸入正整數的成績.");
     status = true;
    }
   } while (status);
  }

  System.out.println("\n開始輸出學生成績");
  for(int i = 0; i < grade.length; i++){
   System.out.println("學生 " + grade[i].getSid() + " 成績 " + grade[i].getGrade());
  }
  System.out.println("\n最高最低成績");
  System.out.println("最高成績 第 " + grade[maxid].getSid() + " 號學生成績" + grade[maxid].getGrade());
  System.out.println("最低成績 第 " + grade[minid].getSid() + " 號學生成績" + grade[minid].getGrade());

  System.out.println("\n平均成績 " + (float)sum/(float)grade.length);

  System.out.println("\n成績排行榜");

  // Sort by grade via bubble sort
  System.out.print("成績排序中 ");
  for(int i = grade.length - 1; i > 0; i--){
   for(int j = 0; j < i; j++){
    if(grade[j+1].getGrade() > grade[j].getGrade()){
     // swap
     Student tmpgr = grade[j+1];
     grade[j+1] = grade[j];
     grade[j] = tmpgr;
     scount++;
     System.out.print("s");
    } else {
     System.out.print(".");
    }
    ccount++;
   }
  }
  System.out.println("\nSwap / Total comparison : " + scount + " / " + ccount);

  System.out.println("\n成績排序結果");
  int rank = 1;
  for(int i = 0; i < grade.length; i++){
   if( i != 0 && grade[i].getGrade() != grade[i-1].getGrade() ){ rank++; }
   System.out.println("名次 " + (rank) + " 第 " + grade[i].getSid() + " 號學生成績 " + grade[i].getGrade());
  }
 }
}

方法三 方法二的進化版. 將最後交換位置設為 sentinel, 讓比較次數減少.
程式碼

import java.io.*;

class C7P155_2
{
 public static void main(String[] args) throws IOException
 {
  int student_num = 0, maxgr = 0, mingr = 0, maxid = 0, minid = 0, sum = 0, scount = 0, ccount = 0;
  boolean status = false;
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

  System.out.println("學生成績分析程式 ");
  do{
   System.out.print("請輸入學生人數 ");
   try{
    student_num = Integer.parseInt(br.readLine());
    status = false;
   } catch ( NegativeArraySizeException e ){
    System.out.println("請輸入正整數的學生人數.");
    status = true;
   } catch ( NumberFormatException e ){
    System.out.println("請輸入學生人數.");
    status = true;
   }
  } while (status);

  int grade[] = new int[student_num];

  System.out.println("\n開始輸入學生成績");

  for(int i = 0; i < student_num; i++){
   status = false;
   do{
    System.out.print("學生 " + (i+1) + " 成績 ");
    try{
     grade[i] = Integer.parseInt(br.readLine());
     sum += grade[i];
     if( i == 0 ){
      maxgr = mingr = grade[i];
     }else{
      if(grade[i] > maxgr){
       maxgr = grade[i]; maxid = i;
      } else if(grade[i] < mingr){
       mingr = grade[i]; minid = i;
      }
     }
     status = false;
    } catch ( NumberFormatException e ){
     System.out.println("請輸入正整數的成績.");
     status = true;
    }
   } while (status);
  }

  System.out.println("\n開始輸出學生成績");
  for(int i = 0; i < grade.length; i++){
   System.out.println("學生 " + (i+1) + " 成績 " + grade[i]);
  }
  System.out.println("\n最高最低成績");
  System.out.println("最高成績 第 " + (maxid+1) + " 號學生成績" + grade[maxid]);
  System.out.println("最低成績 第 " + (minid+1) + " 號學生成績" + grade[minid]);

  System.out.println("\n平均成績 " + (float)sum/(float)grade.length);

  System.out.println("\n成績排行榜");
  // Generate student id array
  int stid[] = new int[grade.length];
  for(int i = 0; i < grade.length; i++){ stid[i] = i; }

  // Sort by grade via bubble sort
  System.out.print("成績排序中 ");
  for(int i = grade.length - 1, lastj = grade.length - 1; i > 0; i--){
   // For debug
   // System.out.print("(" + i + ")[" + lastj + "]");
   boolean swapstatus = false;
   for(int j = 0; j < i; j++){
    if(grade[j+1] > grade[j]){
     // swap
     int tmpgr = grade[j+1];
     int tmpid = stid[j+1];
     grade[j+1] = grade[j];
     stid[j+1] = stid[j];
     grade[j] = tmpgr;
     stid[j] = tmpid;
     lastj = j;
     swapstatus = true;
     scount++;
     System.out.print("s");
    } else {
     System.out.print(".");
    }
    ccount++;
   }
   if(swapstatus){ i = lastj + 1; } else { break;}
  }
  System.out.println("\nSwap / Total comparison : " + scount + " / " + ccount);

  System.out.println("\n成績排序結果");
  int rank = 1;
  for(int i = 0; i < grade.length; i++){
   if( i != 0 && grade[i] != grade[i-1] ){ rank++; }
   System.out.println("名次 " + (rank) + " 第 " + (stid[i]+1) + " 號學生成績 " + grade[i]);
  }
 }
}

物件導向版

import java.io.*;

class Student
{
 int sid;
 int grade;

 public void setGrade(int sid, int grade)
 {
  this.sid = sid;
  this.grade = grade;
 }

 public int getGrade()
 {
  return this.grade;
 }

 public int getSid()
 {
  return this.sid;
 }
}

class C8P158_2
{
 public static void main(String[] args) throws IOException
 {
  int student_num = 0, maxgr = 0, mingr = 0, maxid = 0, minid = 0, sum = 0, scount = 0, ccount = 0;
  boolean status = false;
  BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

  System.out.println("學生成績分析程式 ");
  do{
   System.out.print("請輸入學生人數 ");
   try{
    student_num = Integer.parseInt(br.readLine());
    status = false;
   } catch ( NegativeArraySizeException e ){
    System.out.println("請輸入正整數的學生人數.");
    status = true;
   } catch ( NumberFormatException e ){
    System.out.println("請輸入學生人數.");
    status = true;
   }
  } while (status);

  Student grade[] = new Student[student_num];

  System.out.println("\n開始輸入學生成績");

  for(int i = 0; i < student_num; i++){
   status = false;
   do{
    System.out.print("學生 " + (i+1) + " 成績 ");
    try{
     grade[i] = new Student();
     grade[i].setGrade( i + 1, Integer.parseInt(br.readLine()) );
     sum += grade[i].getGrade();
     if( i == 0 ){
      maxgr = mingr = grade[i].getGrade();
     }else{
      if(grade[i].getGrade() > maxgr){
       maxgr = grade[i].getGrade(); maxid = i;
      } else if(grade[i].getGrade() < mingr){
       mingr = grade[i].getGrade(); minid = i;
      }
     }
     status = false;
    } catch ( NumberFormatException e ){
     System.out.println("請輸入正整數的成績.");
     status = true;
    }
   } while (status);
  }

  System.out.println("\n開始輸出學生成績");
  for(int i = 0; i < grade.length; i++){
   System.out.println("學生 " + grade[i].getSid() + " 成績 " + grade[i].getGrade());
  }
  System.out.println("\n最高最低成績");
  System.out.println("最高成績 第 " + grade[maxid].getSid() + " 號學生成績" + grade[maxid].getGrade());
  System.out.println("最低成績 第 " + grade[minid].getSid() + " 號學生成績" + grade[minid].getGrade());

  System.out.println("\n平均成績 " + (float)sum/(float)grade.length);

  System.out.println("\n成績排行榜");

  // Sort by grade via bubble sort
  System.out.print("成績排序中 ");
  for(int i = grade.length - 1, lastj = grade.length - 1; i > 0; i--){
   // For debug
   // System.out.print("(" + i + ")[" + lastj + "]");
   boolean swapstatus = false;
   for(int j = 0; j < i; j++){
    if(grade[j+1].getGrade() > grade[j].getGrade()){
     // swap
     Student tmpgr = grade[j+1];
     grade[j+1] = grade[j];
     grade[j] = tmpgr;
     lastj = j;
     swapstatus = true;
     scount++;
     System.out.print("s");
    } else {
     System.out.print(".");
    }
    ccount++;
   }
   if(swapstatus){ i = lastj + 1; } else { break;}
  }
  System.out.println("\nSwap / Total comparison : " + scount + " / " + ccount);

  System.out.println("\n成績排序結果");
  int rank = 1;
  for(int i = 0; i < grade.length; i++){
   if( i != 0 && grade[i].getGrade() != grade[i-1].getGrade() ){ rank++; }
   System.out.println("名次 " + (rank) + " 第 " + grade[i].getSid() + " 號學生成績 " + grade[i].getGrade());
  }
 }
}

測試範例 : 七位學生的成績
範例一 : 1 2 3 4 5 6 7
反轉表 

1 2 3 4 5 6 7
0 1 2 3 4 5 6

方法一 : 21/21.
方法二 : 21/21.
方法三 : 21/21.

範例二 : 7 6 5 4 3 2 1
反轉表 

1 2 3 4 5 6 7
0 0 0 0 0 0 0

方法一 : 0/21.
方法二 : 0/21.
方法三 : 0/6.

範例三 : 5 7 4 1 6 3 2
反轉表 

1 2 3 4 5 6 7
0 1 1 0 0 3 1

方法一 : 6/21.
方法二 : 6/21.
方法三 : 6/14.

範例四 : 1 6 7 4 5 2 3
反轉表 

1 2 3 4 5 6 7
0 1 2 1 2 1 2

方法一 : 9/21.
方法二 : 9/21.
方法三 : 9/15.