我正在写一个程序而且我被困在一个部分，我必须用我的“flight900”文件更改我的第一个数组中某些字符串的结束数。第一个阵列已经按航班号排序，每个人都有-1个行李。我正在使用二进制搜索算法在我的数组中搜索flight900名称，以使它们与字符串值匹配。 我相信我的if-else连锁店出了点问题。永远不满足if条件。我找不到解决方法。这是我的二分搜索算法。
public class binarySort
{
public static void binary(String[] array, String value, String array2[])
{
//Initializing
int middle, first=0, last=67, position=-1, counter=-1;
int result=0,a=0,b=0,c=0,d=0;
boolean found = false;
//binary search
while((!found) && (first<=last))
{
middle = ((first + last)/2);
//These are STRINGS to get the first name from the flight900 list
String str0 = array[middle].substring(6,9);
String str1 = array[middle].substring(6,10);
String str2 = array[middle].substring(6,11);
String str3 = array[middle].substring(6,12);
String str4 = array[middle].substring(6,13);
int answer0=0, answer1=0, answer2=0, answer3=0, answer4=0;
//THESE ARE INTEGERS
//compareTo(); returns 0 if both values are equal, a positive number of the first is bigger,
//and a negative number of the first is smaller
answer0 = str0.compareTo(value);
answer1 = str1.compareTo(value);
answer2 = str2.compareTo(value);
answer3 = str3.compareTo(value);
answer4 = str4.compareTo(value);
counter++;
/*I believe something is wrong in this if-else chain.*/
if((answer0==0)||(answer1==0)||(answer2==0)||(answer3==0)||(answer4==0))
{
found = true;
position = middle;
array[position] = array2[counter];
result = str0.compareTo(value);
}
else if((result >= 0)||(a >= 0)||(b >= 0)||(c >= 0)||(d >= 0))
{
last = (middle -1);
}
else
{
first = (middle + 1);
}
}
}
}
这是我的测试课。一切似乎都在测试器类中工作，它只是二进制部分不起作用。我决定在另一个类中进行二进制搜索，因为它开始变得无组织。
import java.io.*;
import java.util.ArrayList;
import java.util.Arrays;
public class airplane
{
public static void main(String[] args)
{
String FileName = "Reservationrecords.txt";//FileName is the text file name
String line; //line is the line I read
String[] allPassengers = new String[67]; //Store "line" in this array to make the list of passengers
String noOfCheckInBaggage= "-1"; //Everyone starts at -1 bags
//Try to read the file and put it into "allPassengers" array
//If can't read file, prints out error
try
{
BufferedReader input = new BufferedReader(new FileReader(FileName)); //Reads files name
for(int i=0; i<67; i++)
{
allPassengers[i] = input.readLine(); //Populates the array
allPassengers[i] += noOfCheckInBaggage; //Adds "-1" at the end of the element
}
input.close(); //You open a file, read a file, then you must close the file
}
catch (Exception e)
{
System.out.println("Error while reading the file: " + e.getMessage()); //Prints out the error message
}
//This section sorts the "allPassengers" array
int result; //Holds -1 or 0
int minIndex; //Minimum low value
String temp; //Holds a temporary String which is used for swapping
String minValue; //Holds the smallest String
//Insertion sort algorithm for sorting Strings.
for(int startScan = 0; startScan < allPassengers.length-1; startScan++)
{
minIndex = startScan;
minValue = allPassengers[minIndex];
//For-loop to sort the array
for(int index = startScan + 1; index < allPassengers.length; index++)
{
result = allPassengers[index].compareTo(minValue);
if(result < 0)
{
minValue = allPassengers[index];
minIndex = index;
}
}
//Swap function
{
temp = allPassengers[minIndex];
allPassengers[minIndex] = allPassengers[startScan];
allPassengers[startScan] = temp;
}
}
String[] flight900 = new String[14];
try
{
BufferedReader input = new BufferedReader(new FileReader("flight900.txt")); //Reads files name
for(int i=0; i<14; i++)
{
flight900[i] = input.readLine(); //Populates the array
}
input.close(); //You open a file, read a file, then you must close the file
}
catch (Exception e)
{
System.out.println("Error while reading the file: " + e.getMessage()); //Prints out the error message
}
binarySort.binary(allPassengers, "Barnett", flight900);
binarySort.binary(allPassengers, "Berndt", flight900);
binarySort.binary(allPassengers, "Carroll", flight900);
binarySort.binary(allPassengers, "Chen", flight900);
binarySort.binary(allPassengers, "Vijay", flight900);
binarySort.binary(allPassengers, "Chu", flight900);
binarySort.binary(allPassengers, "Zheng", flight900);
binarySort.binary(allPassengers, "Costello", flight900);
binarySort.binary(allPassengers, "Cusumano", flight900);
binarySort.binary(allPassengers, "Dougherty", flight900);
binarySort.binary(allPassengers, "Dyer", flight900);
binarySort.binary(allPassengers, "Eppinger", flight900);
binarySort.binary(allPassengers, "Fernandez", flight900);
binarySort.binary(allPassengers, "Frank", flight900);
for(int index=0; index<67; index++)
{
System.out.println(allPassengers[index]);
}
}
}
这是我在第一个数组中读到的原始文件。
AZ495 Malone, Thomas A1213878 Scorpius
AZ386 Granja, Joao A4567897 Canis
AZ531 EL Miligi, Haytham C3947390 Canis Green peace activist
AZ900 Franck, Travis C6755437 Canis IBN chief researcher
AZ531 Dhanjal, Surinder C9219437 Canis
AZ495 Mende, Paul D1219097 Cancer
AZ386 Hadzima, Joseph D3333123 Virgo
AZ874 Francesco, Monticone D6544678 Eridanus
AZ900 Cusumano, Michael E4543409 Eridanus
AZ874 Zhuoran, Zhao E6577779 Crux
AZ531 Barwreck, Obama E6666666 EridanusHead of international spy ring
AZ531 Misseille, Obama E6666667 Eridanus Advisor of Barwreck Obama
AZ874 Akinc, Bridget F5456776 Virgo
AZ386 Jay, Jason F5459908 Draco
AZ874 Asquith, Paul F5676655 Aquarius
AZ495 Nachtrieb, Robert F7878333 Leo
AZ900 Berndt, Ernst G5643211 Taurus
AZ900 Carroll, John G5656789 Cepheus
AZ531 Cummer, Rick H3947399 Leo
AZ874 Sarfraz, Khurshid I8767890 Leo
AZ386 Bill, Gate I8978999 Taurus
AZ874 Zheng, Wang J8767765 Eridanus
AZ874 Vijay, Garg K7686546 Capricornus
AZ495 Bent, Bernanke K8888909 Taurus Inventor of Hot Money Theory
AZ900 Fernandez, Roberto L7077765 Leo
AZ531 O'Neil, Kevin L8495849 Virgo
AZ531 Alexis, Kwasinski L9875676 Corona CEO of Koyota Motor
AZ531 Babinchuk, Wayne N9847293 Cancer
AZ531 Alan, Bovik O5646324 Draco
AZ386 Isaacs, William O8796234 Cepheus
AZ900 Costello, Anna P7878665 Eridanus
AZ495 Gregory, Nathaniel P8796543 Eridanus
AZ495 Kritzman, Mark P9090888 Eridanus
AZ874 Ackerman, Joshua P9809777 Virgo
AZ874 Andreas, Gerstlauer P9868568 Cepheus
AZ386 Kellogg, Suzuki Q1113133 Corona Founder of Sonny
AZ874 Jeff, Andrews Q2123443 Cancer United Nation negotiator
AZ495 Klein, Janice Q3773331 Cepheus
AZ495 Kogan, Leonid Q7777077 Capricornus
AZ531 Lee, Mahnhoon Q9487400 Taurus
AZ900 Chu, Zen R2000098 Cepheus
AZ900 Vijay, Garg R6567123 Corona
AZ531 Park, Andrew S4957459 Aquarius
AZ874 Sarfraz, Khurshid S5654678 Canis
AZ531 Sharma, Mridula S7654566 Taurus Queen of Ingland
AZ874 Deji, Akinwande S7678769 Canis
AZ495 Little, John S7878653 Crux
AZ531 Rahman, Musfiq S8765567 Corvus
AZ386 Hynes, Tod T2323111 Taurus
AZ900 Eppinger, Steven T2343111 Cancer
AZ386 Jackie, Stewart T7773123 Corvus
AZ874 Andrea, Alu T7777656 Taurus
AZ900 Dyer, Barbara T8888765 Crux
AZ900 Zheng, Wang U1321254 Capricornus
AZ531 Kwiatkowska, Mila U3845738 Virgo
AZ386 Michael, Schumacher U5454231 Aquarius
AZ900 Barnett, Arnold U7678765 Corvus
AZ386 Homer, Jack U8897529 Virgo
AZ874 Bei, Yu U8978999 Scorpius
AZ900 Dougherty, Jim W1232121 Scorpius
AZ531 Mikhail, Belkin W9876661 Cepheus
AZ495 Roberts, Edward X3434222 Virgo
AZ495 Reagans, Ray X6321235 Canis
AZ531 Ahmed, Faheem X6836493 Crux
AZ531 A, Mohd X9878038 Scorpius
AZ495 O'Shea, Rory Y1212332 Canis
AZ900 Chen, Elaine Y7876780 Draco Nobel prize (Beauty)
只是来了，这是我想要更改结束号码的flight900文本文件。
Barnett, Arnold U7678765 0
Berndt, Ernst G5643211 1
Carroll, John G5656789 1
Chen, Elaine Y7876780 1
Vijay, Garg R6567123 -1
Chu, Zen R2000098 2
Zheng, Wang U1321254 0
Costello, Anna P7878665 1
Cusumano, Michael E4543409 1
Dougherty, Jim W1232121 -1
Dyer, Barbara T8888765 2
Eppinger, Steven T2343111 -1
Fernandez, Roberto L7077765 0
Franck, Travis C6755437 2
运行之后，我得到了排序列表的输出，没有任何数字被更改。
AZ386 Bill, Gate I8978999 Taurus -1
AZ386 Granja, Joao A4567897 Canis -1
AZ386 Hadzima, Joseph D3333123 Virgo -1
AZ386 Homer, Jack U8897529 Virgo -1
AZ386 Hynes, Tod T2323111 Taurus -1
AZ386 Isaacs, William O8796234 Cepheus -1
AZ386 Jackie, Stewart T7773123 Corvus -1
AZ386 Jay, Jason F5459908 Draco -1
AZ386 Kellogg, Suzuki Q1113133 Corona Founder of Sonny-1
AZ386 Michael, Schumacher U5454231 Aquarius -1
AZ495 Bent, Bernanke K8888909 Taurus Inventor of Hot Money Theory-1
AZ495 Gregory, Nathaniel P8796543 Eridanus -1
AZ495 Klein, Janice Q3773331 Cepheus -1
AZ495 Kogan, Leonid Q7777077 Capricornus -1
AZ495 Kritzman, Mark P9090888 Eridanus -1
AZ495 Little, John S7878653 Crux -1
AZ495 Malone, Thomas A1213878 Scorpius-1
AZ495 Mende, Paul D1219097 Cancer -1
AZ495 Nachtrieb, Robert F7878333 Leo -1
AZ495 O'Shea, Rory Y1212332 Canis -1
AZ495 Reagans, Ray X6321235 Canis -1
AZ495 Roberts, Edward X3434222 Virgo -1
AZ531 A, Mohd X9878038 Scorpius -1
AZ531 Ahmed, Faheem X6836493 Crux -1
AZ531 Alan, Bovik O5646324 Draco -1
AZ531 Alexis, Kwasinski L9875676 Corona CEO of Koyota Motor-1
AZ531 Babinchuk, Wayne N9847293 Cancer -1
AZ531 Barwreck, Obama E6666666 Eridanus Head of international spy ring-1
AZ531 Cummer, Rick H3947399 Leo -1
AZ531 Dhanjal, Surinder C9219437 Canis -1
AZ531 EL Miligi, Haytham C3947390 Canis Green peace activist-1
AZ531 Kwiatkowska, Mila U3845738 Virgo -1
AZ531 Lee, Mahnhoon Q9487400 Taurus -1
AZ531 Mikhail, Belkin W9876661 Cepheus -1
AZ531 Misseille, Obama E6666667 Eridanus Advisor of Barwreck Obama-1
AZ531 O'Neil, Kevin L8495849 Virgo -1
AZ531 Park, Andrew S4957459 Aquarius -1
AZ531 Rahman, Musfiq S8765567 Corvus -1
AZ531 Sharma, Mridula S7654566 Taurus Queen of Ingland-1
AZ874 Ackerman, Joshua P9809777 Virgo -1
AZ874 Akinc, Bridget F5456776 Virgo -1
AZ874 Andrea, Alu T7777656 Taurus -1
AZ874 Andreas, Gerstlauer P9868568 Cepheus -1
AZ874 Asquith, Paul F5676655 Aquarius -1
AZ874 Bei, Yu U8978999 Scorpius -1
AZ874 Deji, Akinwande S7678769 Canis -1
AZ874 Francesco, Monticone D6544678 Eridanus -1
AZ874 Jeff, Andrews Q2123443 Cancer United Nation negotiator-1
AZ874 Sarfraz, Khurshid I8767890 Leo -1
AZ874 Sarfraz, Khurshid S5654678 Canis -1
AZ874 Vijay, Garg K7686546 Capricornus -1
AZ874 Zheng, Wang J8767765 Eridanus -1
AZ874 Zhuoran, Zhao E6577779 Crux -1
AZ900 Barnett, Arnold U7678765 Corvus -1
AZ900 Berndt, Ernst G5643211 Taurus -1
AZ900 Carroll, John G5656789 Cepheus -1
AZ900 Chen, Elaine Y7876780 Draco Nobel prize (Beauty)-1
AZ900 Chu, Zen R2000098 Cepheus -1
AZ900 Costello, Anna P7878665 Eridanus -1
AZ900 Cusumano, Michael E4543409 Eridanus -1
AZ900 Dougherty, Jim W1232121 Scorpius -1
AZ900 Dyer, Barbara T8888765 Crux -1
AZ900 Eppinger, Steven T2343111 Cancer -1
AZ900 Fernandez, Roberto L7077765 Leo -1
AZ900 Franck, Travis C6755437 Canis IBN chief researcher-1
AZ900 Vijay, Garg R6567123 Corona -1
AZ900 Zheng, Wang U1321254 Capricornus -1
提前谢谢你。我一直在努力解决它。
答案 0 :(得分：0)
这里有很多问题。
您已从行的开头（偏移0）对行进行排序。您正尝试从偏移量0排序数据中的偏移量6进行二分搜索。那永远不会奏效！如果您在偏移量6的行内进行二进制搜索，则应该对相同偏移量的行进行排序，因为如果从偏移量6排序，行的顺序将不同。
请看下面的代码块：
//These are STRINGS to get the first name from the flight900 list
String str0 = array[middle].substring(6,9);
String str1 = array[middle].substring(6,10);
String str2 = array[middle].substring(6,11);
String str3 = array[middle].substring(6,12);
String str4 = array[middle].substring(6,13);
看起来解析列表中的第一个名称是一种可怕的方法。仅仅因为名称的长度不同，您无法尝试创建所有可能的子串并进行比较！您必须使用适当的分隔符解析该行，以便您可以干净地分离出用于比较的名称。那么你就不会有那么多字符串要比较了！
建议：
解析该行并从中创建一个对象。您可以将数据放在自定义类中，甚至可以放在具有键值对的映射中。基本上你应该以解析的格式保存行数据，以便轻松使用内容。
然后，如果要按航班名称搜索，请创建一个地图，其中已解析的航班名称为关键，而已解析的对象为值。现在，要查找任何航班，您可以从地图中的名称中获取值。如果有多个具有相同名称的航班（可能不是这种情况，但我不知道您的数据），那么您应该针对每个航班名称保留一个列表，以保存从每个航线分析的多个航班数据对象。当您查找航班名称时，您将获得与该名称匹配的所有航班的列表。
希望有所帮助！