java - Simple Computing Machine -

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• java: if vs. switch 11 answers

i'm working on von neumann machine, i'm writing java program works simple machine, follows instructions. reads textfile , depending on opcode in file, either stores, adds, substract, multilply, divide , load numbers. should use switch statement or alot of if else statements?

• 01 07 // load 7 accumulator
• 21 91 // store accumulator m1
• 05 13 // add 13 7 , keep 20 in acc.
• 99 99 // print acc. contents
• 06 12 // subtract 12 acc.

• 21 91 // store 8 m1

  public class machine{ public static void main(string[] args) throws filenotfoundexception 

  {

    file file = new file("u:/op.txt");   scanner readfile = new scanner(file);      while(readfile.hasnextint()){       string read = readfile.nextline();        system.out.println(read);     }   } 

use this:

import java.io.*; import java.util.scanner;  public class machine{     public static void main(string[] args) throws filenotfoundexception     {         file file = new file("u:/op.txt");         scanner readfile = new scanner(file);          int acc = 0;         int m1 = 0;          while(readfile.hasnextint())         {             string read = readfile.nextline();              switch(read.substring(0, 2))             {                 case "01":                     acc = m1 + integer.parseint(read.substring(3, 5));                     system.out.println(acc);                 break;             }         }     } } 

the read.substring(0, 2) gets first 2 characters. read.substring(3, 5) gets other 2 , integer.parseint(intstring) gets integer value of these 2 characters.

this can reused examples adding in other cases in switch.