java.util.scanner

I am playing around with the Scanner class for learning purposes and i use it to read a very large file (60.000 lines aprox) without using the Reader class , and it stops reading after approximately 400 lines. Do i have to use a Bufferedreader inside the Scanner's constructor or the problem is something else? I want to know why this is happening. Thanks. My code is the usual code to output all the lines. File file1 = new File("file1"); Scanner in= new Scanner(file1); while (scan.hasNextLine() ) { String str = scan.nextLine(); System.out.println(str); } Ankit Rustagi This issue is usually more

I understand what is Scanner good for, and also when to use Scanner and when BufferedReader. I read a different, yet in some therm similar question Scanner vs. BufferedReader Why is Scanner so slow when I read from the input? I assume it has to do with that there is a small buffer in Scanner, but here I am lost. The original problem is from, Codechef , but I am not interested in that solution. Here is a code example with a given input: Input: 7 3 1 51 966369 7 9 999996 1 And the code import java.io.BufferedReader; import java.io.InputStreamReader; public class Main { public static void main

What I am trying to do is have multiple inputs that all have different variables. Each variable will be part of different equations. I am looking for a way to do this and, I think I have an idea. I just want to know if this would be legal and, if maybe there is a better way to do this. import java.util.*; public class Example{ public static void main(String args[]){ Scanner dd = new Scanner(System.in); System.out.println("Enter number."); int a = dd.nextInt(); System.out.println("Enter number."); int b = dd.nextInt(); System.out.println("Enter number."); int c = dd.nextInt(); } } If every

Basic problem here.. I will start off by asking that you please not respond with any code, as that likely will only confuse me further (programming noob). I am looking for a clear explanation on how to solve this issue that I'm having. I have a scanner that reads input from the user. The user is prompted to enter an int value between 1 to 150 (whole numbers only). I obtain the value as follows: Scanner scan = new Scanner(System.in); int input = scan.nextInt(); And continue on with my program, and everything works fine. Unfortunately, the code isn't exactly bulletproof, since any input that is

This question already has an answer here: How to use java.util.Scanner to correctly read user input from System.in and act on it? 1 answer Basically, my situation requires me to check to see if the String that is defined by user input from the keyboard is only alphabetical characters in one case and only digits in another case. This is written in Java. my current code: switch (studentMenu) { case 1: // Change all four fields System.out.println("Please enter in a first name: "); String firstNameIntermediate = scan.next(); firstName = firstNameIntermediate.substring(0,1).toUpperCase() +

I'm reading 2 csv files: store_inventory & new_acquisitions . I want to be able to compare the store_inventory csv file with new_acquisitions . 1) If the item names match just update the quantity in store_inventory. 2) If new_acquisitions has a new item that does not exist in store_inventory , then add it to the store_inventory . Here is what i have done so far but its not very good. I added comments where i need to add taks 1 & 2 . Any advice or code to do the above tasks would be great! thanks. File new_acq = new File("/src/test/new_acquisitions.csv"); Scanner acq_scan = null; try { acq_scan