Convert Hex To Dec in java with HashMap.. I\'m making a compiler for assembler i

Question

Convert Hex To Dec in java with HashMap..

I'm making a compiler for assembler in JAVA. My program after several processes leaves a text file as follows. example.ASM file with this:

CLO
Start:
MOV AL,0
OUT 01
MOV AL,FC
OUT 01
JMP Start
END

In my program i have a hash map like this.

HashMap<String, String> myObjs =new HashMap<>();
  
myObjs.put("MOV","D0");
myObjs.put("END","A0");
myObjs.put("SUB","A1");
myObjs.put("MUL","A2");
myObjs.put("DIV","A3");
myObjs.put("JMP","A4");
myObjs.put("AND","AA");
myObjs.put("AL","AB");
myObjs.put("OUT","C4");
myObjs.put("Start","C6");
myObjs.put("CLO","CA");

How can I by means of that hashmap convert the commands to his assigned hexadecimal value?

Sample program output for example.ASM file:

CA C6 D0 AB 0 C4 01 D0 AB FC C4 01 A4 C6 A0

Explanation / Answer

Hi,

Below is the TestMain.java, which takes example.ASM as input and reads the hashmap and provides its corresponsing values as output.

package decToHexaDec;

import java.io.File;

import java.io.FileNotFoundException;

import java.util.HashMap;

import java.util.Scanner;

public class TestMain {

public static void main(String[] args) {

HashMap<String, String> myObjs = new HashMap<>();

myObjs.put("MOV", "D0");

myObjs.put("END", "A0");

myObjs.put("SUB", "A1");

myObjs.put("MUL", "A2");

myObjs.put("DIV", "A3");

myObjs.put("JMP", "A4");

myObjs.put("AND", "AA");

myObjs.put("AL", "AB");

myObjs.put("OUT", "C4");

myObjs.put("Start", "C6");

myObjs.put("CLO", "CA");

//calls the method to read file and to store the output, provide the input file path as parameter

String output = readFile(myObjs, "D:\workspace\Test\src\decToHexaDec\example.ASM");

//print the output

System.out.println(output);

}

/**

* @param Hashmap, fileName

* @return list of key values for the given input file

*/

public static String readFile(HashMap<String, String> map, String fileName) {

//to scan the values from the file

Scanner in;

String out ="";

try {

//stores the contents from example.ASM file

in = new Scanner(new File(fileName));

String line;

// checks if file has more lines

while (in.hasNextLine()) {

line = in.nextLine();

//splits the lines when there is space or comma(,)

String tokens[] = line.split(",|\s");

//loop to go through each command available in input file

for (int i = 0; i < tokens.length; i++) {

//replces the special character ":" if available in the command

String temp = tokens[i].replace(":", "");

//gets the value of key in the map and stores   

temp = map.get(temp);

//if value of corresponding key is not available assigns the original command

if (temp == null)

temp = tokens[i];

//adds to the out String where all the values of corresponding keys are stored.

out=out+" "+temp;

}

}

// close scanner

in.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

}

return out;

}

}

Sample Output:

Input: example.ASM

CLO
Start:
MOV AL,0
OUT 01
MOV AL,FC
OUT 01
JMP Start
END

Output:

CA C6 D0 AB 0 C4 01 D0 AB FC C4 01 A4 C6 A0

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