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Creating truth tables in Java

I am trying to print some truth tables as part of a school assignment. How to create dynamic size truth table in Java?

To printTruthTable(1)print:

0
1

printTruthTable(3) Fingerprints:

0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1

Etc. I am trying to implement it using recursion, but I just can't figure it out.

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7 answers

here I will take your problem, everything is written beautifully and tightly in a small class, just copy / paste

Notice how I used modulo2 (% sign) to get 0 and 1 from the loop indices

public class TruthTable {
    private static void printTruthTable(int n) {
        int rows = (int) Math.pow(2,n);

        for (int i=0; i<rows; i++) {
            for (int j=n-1; j>=0; j--) {
                System.out.print((i/(int) Math.pow(2, j))%2 + " ");
            }
            System.out.println();
        }
    }
    public static void main(String[] args) {
        printTruthTable(3); //enter any natural int
    }
}
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- , . Java Integer.toBinaryString , ; .

int n = 3;
for (int i = 0 ; i != (1<<n) ; i++) {
    String s = Integer.toBinaryString(i);
    while (s.length() != 3) {
        s = '0'+s;
    }
    System.out.println(s);
}
+8

:

public static void main(String args[]) {
    int size = 3;
    generateTable(0, size, new int[size]);
}

private static void generateTable(int index, int size, int[] current) {
    if(index == size) { // generated a full "solution"
        for(int i = 0; i < size; i++) {
            System.out.print(current[i] + " ");
        }
        System.out.println();
    } else {
        for(int i = 0; i < 2; i++) {
            current[index] = i;
            generateTable(index + 1, size, current);
        }
    }
}
+2

, , , -, . 2 ^ (n) - 1 .

+1

, , 0 (1 <

public void  generate(int n){
    for (int i=0 ;i!=(1<<n);i++) {
        String binaryRep = Integer.toBinaryString(i);
        while (s.length() != n) {
            binaryRep = '0'+binaryRep;
        }
        System.out.println(s);
    }
}

:

public void generateRecursively(int i , int n){
    if(i==(1<<n))
        return;
    else{
        String temp = Integer.toBinaryString(i);
        while(temp.length()<n){
            temp = '0'+temp;
        }
        System.out.println(temp);
        generateRecursively(i+1,n);
    }
}
0

import java.util.Scanner;
    public class tt{
        boolean arr[][];
        boolean b=false;
        boolean[][] printtt(int n){
            for(int i=0;i<n;i++){
                for(int j=0;j<(Math.pow(2,n));j++){

                        if(j<Math.pow(2,n-1)){
                            arr[j][i]=b;
                        }
                        else{
                            arr[j][i]=!b;
                        }
                }
                }
                return(arr);
            }


        public static void main(String args[]){
            Scanner sc=new Scanner(System.in);
            System.out.println("Input values count");
            tt ob=new tt();
            int num=sc.nextInt();int pownum=(int)Math.pow(2,num);
            boolean array[][]=new boolean[pownum][num];
            array=ob.printtt(num);
            for(int i=0;i<num;i++){
            for(int j=0;j<(Math.pow(2,num));j++){

                    System.out.println(array[j][i]);
                }
        }
    }
    }
0

I had to do something similar recently, except that the project was supposed to generate a truth table for a given logical expression. This is what I came up with to assign independent variables their truth values.

    column = 0;

    while (column < numVariables)
    {
        state = false;
        toggle = (short) Math.pow(2, numVariables - column - 1);

        row = 1;
        while (row < rows)
        {
            if ((row -1)%toggle == 0)
                state = !state;

            if (state)
                truthTable[row][column] = 'T';
            else
                truthTable[row][column] = 'F';

            row++;
        }

        column++;
    }

This assumes your first line is populated with variable names and subexpressions. The math may change a bit if you want to start at line 0.

This bit ....

if ((line -1)% toggle == 0)

will ....

if (line% toggle == 0)

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