bluej Programs

1. Write a program to design a truth table.

import java.util.*;
class truthtable
{
    Scanner sc= new Scanner(System.in);
    int n,r,c,ch;char table[][];
    void input()
    {
        System.out.println("Enter total number of literals:");
        n=sc.nextInt();
        if(n>=1 && n<=4)
        {
            r=(int)Math.pow(2,n);
            c=n+1;
            table=new char[r][c];
        }
    }
    void combination()
    {
        for(int i=0;i<r;i++)
        {
            String v=binary(i,n);//System.out.println(v);
            for(int j=0;j<c-1;j++)
            {
                char ch=v.charAt(j);
                table[i][j]=ch;
            }
        }
    }
    String binary(int i,int n)
    {
        String val="",v1="",v2="";
        while(i!=0)
        {
            int r=i%2;
            val=val+Integer.toString(r);
            i=i/2;
        }
        val=reverse(v2,val,val.length()-1);
        for(int x=0;x<(n-val.length());x++)
        {
            v1+="0";
        }
        val=v1+val;
        return val;
    }
    String reverse(String v2,String val,int l)
    {
      if(l==-1)
      return v2;
      else
      {
          v2+=val.charAt(l);
          return(reverse(v2,val,l-1));
      }
    }
    void ORgate()
    {
        int f=0;
        for(int i=0;i<r;i++)
        {
            for(int j=0;j<c-1;j++)
            {
                if(table[i][j]=='1')
                {
                    f=1;break;
                }
            }
            if(f==1)
            {
                table[i][c-1]='1';
            }
            else
            table[i][c-1]='0';
            f=0;
        }
    }
    void ANDgate()
    {
        int f=0;
        for(int i=0;i<r;i++)
        {
            for(int j=0;j<c-1;j++)
            {
                if(table[i][j]=='0')
                {
                    f=1;break;
                }
            }
            if(f==1)
            {
                table[i][c-1]='0';
            }
            else
            table[i][c-1]='1';
            f=0;
        }
    }
    void NOTgate()
    {
        
        for(int i=0;i<r;i++)
        {
            
            
                if(table[i][0]=='1')
                {
                    table[i][1]='0';
                }
           else
                table[i][1]='1';
            }
    }
    void display(int ch)
    {
        System.out.println("The truth table is:");
        if(n==1)
        System.out.println("p\tp");
        else if(n==2)
        {
            if(ch==1)
            {
                System.out.println("p\tq\tp+q");
            }
            else if(ch==2)
            {
                System.out.println("p\tq\tp.q");
            }
        }
        else if(n==3)
        {
          if(ch==1)
            {
                System.out.println("p\tq\tr\tp+q+r");
            }
            else if(ch==2)
            {
                System.out.println("p\tq\tr\tp.q.r");
            }  
        }
        else
        {
            if(ch==1)
            {
                System.out.println("p\tq\tr\ts\tp+q+r+s");
            }
            else if(ch==2)
            {
                System.out.println("p\tq\tr\ts\tp.q.r.s");
            }
        }
    
        for(int i=0;i<r;i++)
        {
            for(int j=0;j<c;j++)
            {
                System.out.print(table[i][j]+"\t");
            }
            System.out.println();
        }
    }
    void main()
    {
        truthtable ob=new truthtable();
        ob.input();
        ob.combination();
        System.out.println("1:OR gate\n2:AND  gate\n3:NOT gate\nEnter ur choice:");
		ch=sc.nextInt();
        switch(ch)
        {
            case 1:if(ob.n>1)
                    {ob.ORgate();
                     ob.display(ch);
                    }
                    else
                    System.out.println("Minimum inputs should be 2 for OR gate");
            break;
            case 2: if(ob.n>1)
                    {
                     ob.ANDgate();
                      ob.display(ch);
                    }
                    else
                    System.out.println("Minimum inputs should be 2 for AND gate");
                    break;
            case 3:if(ob.n>1)
                    System.out.println("Minimum and Maximuminputs should be 1 for NOT gate");
                    else
                    {
                        ob.NOTgate();
                        ob.display(ch);
                    }
                    break;
            default:
                System.out.println("Wrong Input");
                        
        }
    }
}

Output:

Enter total number of literals:
3
1:OR gate
2:AND  gate
3:NOT gate
Enter ur choice:
1
The truth table is:
p	q	r	p+q+r
0	0	0	0	
0	0	1	1	
0	1	0	1	
0	1	1	1	
1	0	0	1	
1	0	1	1	
1	1	0	1	
1	1	1	1	
Enter total number of literals:
3
1:OR gate
2:AND  gate
3:NOT gate
Enter ur choice:
2
The truth table is:
p	q	r	p.q.r
0	0	0	0	
0	0	1	0	
0	1	0	0	
0	1	1	0	
1	0	0	0	
1	0	1	0	
1	1	0	0	
1	1	1	1
Enter total number of literals:
1
1:OR gate
2:AND  gate
3:NOT gate
Enter ur choice:
3
The truth table is:
p	p
0	1	
1	0