为什么下面的代码没有产生正确的输出？
why is following code not producing the right output?
您被要求使用 Java 代码编写国家橄榄球联盟 (NFL) 传球和接球统计报告。四分卫和外接手有一些共同的信息，但其他信息是针对他们的位置的。
玩家Class
public class Player {
String firstName;
String lastName;
String team;
String position;
public Player(String firstName, String lastName, String team, String position)
{
super();
this.firstName = firstName;
this.lastName = lastName;
this.team = team;
this.position = position;
}
public String getFirstName()
{
return firstName;
}
public void setFirstName(String firstName)
{
this.firstName = firstName;
}
public String getLastName()
{
return lastName;
}
public void setLastName(String lastName)
{
this.lastName = lastName;
}
public String getTeam()
{
return team;
}
public void setTeam(String team)
{
this.team = team;
}
public String getPosition()
{
return position;
}
public void setPosition(String position)
{
this.position = position;
}
}
四分卫Class
public class Quarterback extends Player {
int completions;
int attempts;
int yards;
public Quarterback(String firstName, String lastName, String team,
String position, int completions, int attempts, int yards)
{
super(firstName, lastName, team, position);
this.completions = completions;
this.attempts = attempts;
this.yards = yards;
}
public int getCompletions()
{
return completions;
}
public void setCompletions(int completions)
{
this.completions = completions;
}
public int getAttempts()
{
return attempts;
}
public void setAttempts(int attempts)
{
this.attempts = attempts;
}
public int getYards()
{
return yards;
}
public void setYards(int yards)
{
this.yards = yards;
}
public double percent()
{
return ((double) completions / (double) attempts) * 100.0d;
}
public double yardsPerAttempt()
{
return (double) yards / (double) attempts;
}
public double yardsPerGame()
{
return (double) yards / (double) 16.0d;
}
}
接收者Class
public class Receiver extends Player{
int receptions;
int yards;
public Receiver(String firstName, String lastName, String team,
String position, int receptions, int yards)
{
super(firstName, lastName, team, position);
this.receptions = receptions;
this.yards = yards;
}
public int getReceptions()
{
return receptions;
}
public void setReceptions(int receptions)
{
this.receptions = receptions;
}
public int getYards()
{
return yards;
}
public void setYards(int yards)
{
this.yards = yards;
}
public double yardsPerReception()
{
return (double) yards / (double) receptions;
}
public double yardsPerGame()
{
return (double) yards / 16.0d;
}
}
下面是我在显示输出时出现问题的地方。
import java.io.File;
import java.util.Scanner;
public class NFLTestPlayer
{
public static void main(String[] args)
{
Scanner scanner = null;
try
{
Player players[] = new Player[20];
scanner = new Scanner(new File("nfl.txt"));
int count = 0;
while (scanner.hasNext())
{
String firstName, lastName, team, position;
firstName = scanner.next();
lastName = scanner.next();
team = scanner.next();
position = scanner.next();
if (position.equals("QB"))
{
int completions, attempts, yards;
completions = scanner.nextInt();
attempts = scanner.nextInt();
yards = scanner.nextInt();
players[count++] = new Quarterback(firstName, lastName,
team, position, completions, attempts, yards);
}
else if (position.equals("WR"))
{
int receptions;
int yards;
receptions = scanner.nextInt();
yards = scanner.nextInt();
players[count++] = new Receiver(firstName, lastName, team,
position, receptions, yards);
}
}
System.out.println("NFL 2018 Player Passing/Receiving Statistics\n");
System.out.println("Quarterbacks");
System.out.printf("%-25s %-5s %12s %12s %12s %12s %12s %12s\n",
"Player","Team", "Comp","Att","Pct","Yds","Yds/A","Yds/G");
for (int i = 0; i < players.length; i++)
{
if (players[i] instanceof Quarterback)
{
Quarterback quarterback = (Quarterback) players[i];
System.out.printf("%-25s %-5s %12.0f %12.0f %12.0f %12.1f %12.2f %12d",
quarterback.getFirstName()
+ "," + quarterback.getLastName()
+ quarterback.getTeam()
+ quarterback.getCompletions()
+ quarterback.getAttempts()
+ quarterback.getYards()
+quarterback.yardsPerAttempt()
+quarterback.yardsPerGame());
}
}
System.out.println("\n");
System.out.println("Wide Receivers");
System.out.printf("%-25s %-5s %12s %12s %12s %12s\n",
"Player","Team", "Rec", "Yds","Yds/R","Yds/G");
for (int i = 0; i < players.length; i++)
{
if (players[i] instanceof Receiver)
{
Receiver receiver = (Receiver) players[i];
System.out.printf("%-25s %-5s %12.0f %12.0f %12.0f %12.1f",
receiver.getFirstName()
+ "," + receiver.getLastName()
+ receiver.getTeam()
+ receiver.getReceptions()
+ receiver.getYards()
+ receiver.yardsPerReception()
+ receiver.yardsPerGame());
}
}
} catch (Exception e)
{
e.printStackTrace();
}
}
}
输出应使用以下文本文件创建 table：
nfl.txt
Ben Roethlisberger PIT QB 452 675 5129
Julio Jones ATL WR 113 1677
Aaron Rodgers GB QB 372 597 4442
Patrick Mahomes KC QB 383 580 5097
JuJuj Smith-Schuster PIT WR 111 1426
Philip Rivers LAC QB 347 508 4308
DeAndre Hopkins HOU WR 115 1572
Mike Evans TB WR 86 1524
Matt Ryan ATL QB 422 608 4924
Davante Adams GB WR 111 1386
Tyreek Hill KC WR 87 1479
Michael Thomas NO WR 125 1405
Jared Goff LAR QB 364 561 4688
Andrew Luck IND QB 430 639 4593
Adam Thielen MIN WR 113 1373
Eli Manning NYG QB 380 576 4299
Kirk Cousins MIN QB 425 606 4298
Robert Woods LAR WR 86 1219
Tom Brady NE QB 375 570 4355
Brandin Cooks LAR WR 80 1204
NFL 2018 Player Passing/Receiving Statistics
Quarterbacks
Player Team Comp Att Pct Yds Yds/A Yds/6
Brady,Tom NE 375 570 66. 4,355 8. 272
Cousins,Kirk MIN 425 606 70. 4,298 7. 268
Goff,jared LAR 364 561 65. 4,688 8. 293
Luck,Andrew IND 430 639 67. 4,593 7. 287
Mahomes,Patrick KC 383 580 66.0 5,097 9. 318
Manning,Eli NYG 380 576 66.0 4,299 7. 268
Rivers,Philip LAC 347 508 68. 4,308 8. 269
Rodgers,Aaron GB 372 597 62. 4,442 7. 277
Roethlisberger, PIT 452 675 67.0 5,129 7.60 320
Ryan,Matt ATL 422 608 69. 4,924 8.10 307
Receivers
Player Team Rec Yds Yds/R Yds/6
Adams,Davante G8 111 1,386 13. 87.
Cooks,Brandin LAR 80 1,204 15. 75.
Evans,Mike TB 86 1,524 18. 95.
Hill,Tyreek KC 87 1,479 17.0 92.
Hopkins,DeAndre HOU 115 1,572 14. 98.
lonesOullo ATL 113 1,677 15. 105.
Smith-Schuster,JuJu PIT 111 1,426 13. 89.
Thielen,Adam KIN 113 1,373 12. 86.
Thomas,Michael NO 125 1,405 11. 88.
Woods,Robert LAR 86 1,219 14. 76.
你能更清楚一点，解释一下你面临的问题是什么吗？你有什么错误吗？还是输出不一样？
我要冒险了，想知道你是否遇到了 java.util.MissingFormatArgumentException 例外？
编辑：
好的，这是有原因的 - 您的格式设置不正确。这是另一个问题的重复：
System.out.printf("%-25s %-5s %12.0f %12.0f %12.0f %12.1f %12.2f",
quarterback.getFirstName() + " " + quarterback.getLastName(), quarterback.getTeam(), (double)quarterback.getCompletions(), (double)quarterback.getAttempts(), (double)quarterback.getYards(), quarterback.yardsPerAttempt(), quarterback.yardsPerGame());
System.out.println("/n");
但是，我强烈建议您阅读有关使用说明符进行格式化的内容。您收到该异常的原因是您没有将变量正确关联到说明符。
您被要求使用 Java 代码编写国家橄榄球联盟 (NFL) 传球和接球统计报告。四分卫和外接手有一些共同的信息，但其他信息是针对他们的位置的。
玩家Class
public class Player {
String firstName;
String lastName;
String team;
String position;
public Player(String firstName, String lastName, String team, String position)
{
super();
this.firstName = firstName;
this.lastName = lastName;
this.team = team;
this.position = position;
}
public String getFirstName()
{
return firstName;
}
public void setFirstName(String firstName)
{
this.firstName = firstName;
}
public String getLastName()
{
return lastName;
}
public void setLastName(String lastName)
{
this.lastName = lastName;
}
public String getTeam()
{
return team;
}
public void setTeam(String team)
{
this.team = team;
}
public String getPosition()
{
return position;
}
public void setPosition(String position)
{
this.position = position;
}
}
四分卫Class
public class Quarterback extends Player {
int completions;
int attempts;
int yards;
public Quarterback(String firstName, String lastName, String team,
String position, int completions, int attempts, int yards)
{
super(firstName, lastName, team, position);
this.completions = completions;
this.attempts = attempts;
this.yards = yards;
}
public int getCompletions()
{
return completions;
}
public void setCompletions(int completions)
{
this.completions = completions;
}
public int getAttempts()
{
return attempts;
}
public void setAttempts(int attempts)
{
this.attempts = attempts;
}
public int getYards()
{
return yards;
}
public void setYards(int yards)
{
this.yards = yards;
}
public double percent()
{
return ((double) completions / (double) attempts) * 100.0d;
}
public double yardsPerAttempt()
{
return (double) yards / (double) attempts;
}
public double yardsPerGame()
{
return (double) yards / (double) 16.0d;
}
}
接收者Class
public class Receiver extends Player{
int receptions;
int yards;
public Receiver(String firstName, String lastName, String team,
String position, int receptions, int yards)
{
super(firstName, lastName, team, position);
this.receptions = receptions;
this.yards = yards;
}
public int getReceptions()
{
return receptions;
}
public void setReceptions(int receptions)
{
this.receptions = receptions;
}
public int getYards()
{
return yards;
}
public void setYards(int yards)
{
this.yards = yards;
}
public double yardsPerReception()
{
return (double) yards / (double) receptions;
}
public double yardsPerGame()
{
return (double) yards / 16.0d;
}
}
下面是我在显示输出时出现问题的地方。
import java.io.File;
import java.util.Scanner;
public class NFLTestPlayer
{
public static void main(String[] args)
{
Scanner scanner = null;
try
{
Player players[] = new Player[20];
scanner = new Scanner(new File("nfl.txt"));
int count = 0;
while (scanner.hasNext())
{
String firstName, lastName, team, position;
firstName = scanner.next();
lastName = scanner.next();
team = scanner.next();
position = scanner.next();
if (position.equals("QB"))
{
int completions, attempts, yards;
completions = scanner.nextInt();
attempts = scanner.nextInt();
yards = scanner.nextInt();
players[count++] = new Quarterback(firstName, lastName,
team, position, completions, attempts, yards);
}
else if (position.equals("WR"))
{
int receptions;
int yards;
receptions = scanner.nextInt();
yards = scanner.nextInt();
players[count++] = new Receiver(firstName, lastName, team,
position, receptions, yards);
}
}
System.out.println("NFL 2018 Player Passing/Receiving Statistics\n");
System.out.println("Quarterbacks");
System.out.printf("%-25s %-5s %12s %12s %12s %12s %12s %12s\n",
"Player","Team", "Comp","Att","Pct","Yds","Yds/A","Yds/G");
for (int i = 0; i < players.length; i++)
{
if (players[i] instanceof Quarterback)
{
Quarterback quarterback = (Quarterback) players[i];
System.out.printf("%-25s %-5s %12.0f %12.0f %12.0f %12.1f %12.2f %12d",
quarterback.getFirstName()
+ "," + quarterback.getLastName()
+ quarterback.getTeam()
+ quarterback.getCompletions()
+ quarterback.getAttempts()
+ quarterback.getYards()
+quarterback.yardsPerAttempt()
+quarterback.yardsPerGame());
}
}
System.out.println("\n");
System.out.println("Wide Receivers");
System.out.printf("%-25s %-5s %12s %12s %12s %12s\n",
"Player","Team", "Rec", "Yds","Yds/R","Yds/G");
for (int i = 0; i < players.length; i++)
{
if (players[i] instanceof Receiver)
{
Receiver receiver = (Receiver) players[i];
System.out.printf("%-25s %-5s %12.0f %12.0f %12.0f %12.1f",
receiver.getFirstName()
+ "," + receiver.getLastName()
+ receiver.getTeam()
+ receiver.getReceptions()
+ receiver.getYards()
+ receiver.yardsPerReception()
+ receiver.yardsPerGame());
}
}
} catch (Exception e)
{
e.printStackTrace();
}
}
}
输出应使用以下文本文件创建 table：
nfl.txt
Ben Roethlisberger PIT QB 452 675 5129
Julio Jones ATL WR 113 1677
Aaron Rodgers GB QB 372 597 4442
Patrick Mahomes KC QB 383 580 5097
JuJuj Smith-Schuster PIT WR 111 1426
Philip Rivers LAC QB 347 508 4308
DeAndre Hopkins HOU WR 115 1572
Mike Evans TB WR 86 1524
Matt Ryan ATL QB 422 608 4924
Davante Adams GB WR 111 1386
Tyreek Hill KC WR 87 1479
Michael Thomas NO WR 125 1405
Jared Goff LAR QB 364 561 4688
Andrew Luck IND QB 430 639 4593
Adam Thielen MIN WR 113 1373
Eli Manning NYG QB 380 576 4299
Kirk Cousins MIN QB 425 606 4298
Robert Woods LAR WR 86 1219
Tom Brady NE QB 375 570 4355
Brandin Cooks LAR WR 80 1204
NFL 2018 Player Passing/Receiving Statistics
Quarterbacks
Player Team Comp Att Pct Yds Yds/A Yds/6
Brady,Tom NE 375 570 66. 4,355 8. 272
Cousins,Kirk MIN 425 606 70. 4,298 7. 268
Goff,jared LAR 364 561 65. 4,688 8. 293
Luck,Andrew IND 430 639 67. 4,593 7. 287
Mahomes,Patrick KC 383 580 66.0 5,097 9. 318
Manning,Eli NYG 380 576 66.0 4,299 7. 268
Rivers,Philip LAC 347 508 68. 4,308 8. 269
Rodgers,Aaron GB 372 597 62. 4,442 7. 277
Roethlisberger, PIT 452 675 67.0 5,129 7.60 320
Ryan,Matt ATL 422 608 69. 4,924 8.10 307
Receivers
Player Team Rec Yds Yds/R Yds/6
Adams,Davante G8 111 1,386 13. 87.
Cooks,Brandin LAR 80 1,204 15. 75.
Evans,Mike TB 86 1,524 18. 95.
Hill,Tyreek KC 87 1,479 17.0 92.
Hopkins,DeAndre HOU 115 1,572 14. 98.
lonesOullo ATL 113 1,677 15. 105.
Smith-Schuster,JuJu PIT 111 1,426 13. 89.
Thielen,Adam KIN 113 1,373 12. 86.
Thomas,Michael NO 125 1,405 11. 88.
Woods,Robert LAR 86 1,219 14. 76.
你能更清楚一点，解释一下你面临的问题是什么吗？你有什么错误吗？还是输出不一样？
我要冒险了，想知道你是否遇到了 java.util.MissingFormatArgumentException 例外？
编辑：
好的，这是有原因的 - 您的格式设置不正确。这是另一个问题的重复：
System.out.printf("%-25s %-5s %12.0f %12.0f %12.0f %12.1f %12.2f",
quarterback.getFirstName() + " " + quarterback.getLastName(), quarterback.getTeam(), (double)quarterback.getCompletions(), (double)quarterback.getAttempts(), (double)quarterback.getYards(), quarterback.yardsPerAttempt(), quarterback.yardsPerGame());
System.out.println("/n");
但是，我强烈建议您阅读有关使用说明符进行格式化的内容。您收到该异常的原因是您没有将变量正确关联到说明符。