Binary search

This technique uses a binary search to find a target integer in a RandomAccessFile. It is just concerned with integers.
This is the code:
//determines if a target number is in a RandomAccessFile using a binary search
//tracks the number of times it took to find that the number was/wasn't in the file
public static void binarySearch(){
Scanner input = new Scanner(System.in);
int target = 0; //the number being searched for
boolean targetFound = false; //indicates if the target is found
int searchCount = 0; //the number of times it took to find that the number was/wasn't in the file
System.out.print("Please enter the number you wish to search for: "); target = input.nextInt(); try{ RandomAccessFile raf = new RandomAccessFile("Project10.dat", "r"); long low = 0; long high = raf.length() - 1; int cur = 0; while(high >= low){ long mid = (low + high) / 2; raf.seek(mid); cur = raf.readInt(); System.out.println(cur); //for debugging searchCount++; if(target < cur){ high = mid - 4; } else if(target == cur){ targetFound = true; break; } else{ low = mid + 4; } } raf.close(); } catch(FileNotFoundException e){ e.printStackTrace(); } catch (IOException e){ e.printStackTrace(); } if(targetFound == true){ System.out.println("The number " + target + " is in the file. It took " + searchCount + " tries to discover this."); } else{ System.out.println("The number " + target + " is not in the file. It took " + searchCount + " tries to discover this."); }
}//end method binarySearch
I've tried everything, but I'm getting the wrong results. Because a raf comprises bytes and an integer contains four bytes, I figured I'd just decrease the high by four and increase the low by four, as described in this blog, where the identical operations were performed by one in a typical binary search. Apparently, this is not the case, and I'm still struggling to understand binary I/O in general. Help?
Answers
Categories
- All Categories
- 158 LFX Mentorship
- 158 LFX Mentorship: Linux Kernel
- 846 Linux Foundation IT Professional Programs
- 389 Cloud Engineer IT Professional Program
- 185 Advanced Cloud Engineer IT Professional Program
- 87 DevOps Engineer IT Professional Program
- 154 Cloud Native Developer IT Professional Program
- 152 Express Training Courses & Microlearning
- 149 Express Courses - Discussion Forum
- 3 Microlearning - Discussion Forum
- 7.1K Training Courses
- 50 LFC110 Class Forum - Discontinued
- 74 LFC131 Class Forum
- 56 LFD102 Class Forum
- 253 LFD103 Class Forum
- 26 LFD110 Class Forum
- 50 LFD121 Class Forum
- 3 LFD123 Class Forum
- 1 LFD125 Class Forum
- 19 LFD133 Class Forum
- 10 LFD134 Class Forum
- 19 LFD137 Class Forum
- 1 LFD140 Class Forum
- 73 LFD201 Class Forum
- 8 LFD210 Class Forum
- 6 LFD210-CN Class Forum
- 2 LFD213 Class Forum - Discontinued
- 128 LFD232 Class Forum - Discontinued
- 3 LFD233 Class Forum
- 5 LFD237 Class Forum
- 25 LFD254 Class Forum
- 739 LFD259 Class Forum
- 111 LFD272 Class Forum - Discontinued
- 4 LFD272-JP クラス フォーラム - Discontinued
- 16 LFD273 Class Forum
- 429 LFS101 Class Forum
- 3 LFS111 Class Forum
- 4 LFS112 Class Forum
- 5 LFS116 Class Forum
- 9 LFS118 Class Forum
- 2 LFS120 Class Forum
- 11 LFS142 Class Forum
- 9 LFS144 Class Forum
- 6 LFS145 Class Forum
- 6 LFS146 Class Forum
- 7 LFS147 Class Forum
- 20 LFS148 Class Forum
- 17 LFS151 Class Forum
- 6 LFS157 Class Forum
- 89 LFS158 Class Forum
- 1 LFS158-JP クラス フォーラム
- 13 LFS162 Class Forum
- 2 LFS166 Class Forum - Discontinued
- 8 LFS167 Class Forum
- 4 LFS170 Class Forum
- 2 LFS171 Class Forum - Discontinued
- 4 LFS178 Class Forum - Discontinued
- 4 LFS180 Class Forum
- 3 LFS182 Class Forum
- 7 LFS183 Class Forum
- 2 LFS184 Class Forum
- 41 LFS200 Class Forum
- 737 LFS201 Class Forum - Discontinued
- 3 LFS201-JP クラス フォーラム - Discontinued
- 22 LFS203 Class Forum
- 141 LFS207 Class Forum
- 3 LFS207-DE-Klassenforum
- 3 LFS207-JP クラス フォーラム
- 302 LFS211 Class Forum - Discontinued
- 56 LFS216 Class Forum - Discontinued
- 60 LFS241 Class Forum
- 51 LFS242 Class Forum
- 39 LFS243 Class Forum
- 17 LFS244 Class Forum
- 8 LFS245 Class Forum
- 1 LFS246 Class Forum
- 1 LFS248 Class Forum
- 120 LFS250 Class Forum
- 3 LFS250-JP クラス フォーラム
- 2 LFS251 Class Forum
- 162 LFS253 Class Forum
- 1 LFS254 Class Forum - Discontinued
- 3 LFS255 Class Forum
- 15 LFS256 Class Forum
- 2 LFS257 Class Forum
- 1.4K LFS258 Class Forum
- 12 LFS258-JP クラス フォーラム
- 139 LFS260 Class Forum
- 165 LFS261 Class Forum
- 44 LFS262 Class Forum
- 82 LFS263 Class Forum - Discontinued
- 15 LFS264 Class Forum - Discontinued
- 11 LFS266 Class Forum - Discontinued
- 25 LFS267 Class Forum
- 27 LFS268 Class Forum
- 38 LFS269 Class Forum
- 11 LFS270 Class Forum
- 202 LFS272 Class Forum - Discontinued
- 2 LFS272-JP クラス フォーラム - Discontinued
- 2 LFS274 Class Forum - Discontinued
- 4 LFS281 Class Forum - Discontinued
- 30 LFW111 Class Forum
- 265 LFW211 Class Forum
- 189 LFW212 Class Forum
- 16 SKF100 Class Forum
- 2 SKF200 Class Forum
- 3 SKF201 Class Forum
- 800 Hardware
- 200 Drivers
- 68 I/O Devices
- 37 Monitors
- 104 Multimedia
- 175 Networking
- 92 Printers & Scanners
- 85 Storage
- 765 Linux Distributions
- 82 Debian
- 67 Fedora
- 20 Linux Mint
- 13 Mageia
- 23 openSUSE
- 149 Red Hat Enterprise
- 31 Slackware
- 13 SUSE Enterprise
- 356 Ubuntu
- 472 Linux System Administration
- 39 Cloud Computing
- 71 Command Line/Scripting
- Github systems admin projects
- 96 Linux Security
- 78 Network Management
- 102 System Management
- 48 Web Management
- 74 Mobile Computing
- 19 Android
- 42 Development
- 1.2K New to Linux
- 1K Getting Started with Linux
- 386 Off Topic
- 119 Introductions
- 178 Small Talk
- 28 Study Material
- 823 Programming and Development
- 310 Kernel Development
- 495 Software Development
- 1.8K Software
- 265 Applications
- 183 Command Line
- 5 Compiling/Installing
- 988 Games
- 318 Installation
- 107 All In Program
- 107 All In Forum
Upcoming Training
-
August 20, 2018
Kubernetes Administration (LFS458)
-
August 20, 2018
Linux System Administration (LFS301)
-
August 27, 2018
Open Source Virtualization (LFS462)
-
August 27, 2018
Linux Kernel Debugging and Security (LFD440)