Prims code

import java.util.*;
import java.lang.*;

import java.util.Scanner;

class excep extends Exception
{
    public String toString()
    {
        return "Enter a valid number of vertices";
    }
}
class solveprims
{
    static void primsmeth(int num,int CM[][])
    {
       Scanner sc=new Scanner(System.in);
        int sv;
        System.out.println("enter the source vertex");
        sv=sc.nextInt();
        System.out.println("The spanning tree edges are");
        int visited[]=new int[num];
        int unvisited[]=new int[num]; 
        for(int i=0;i<num;i++)
         {
             visited[i]=0;
             unvisited[i]=1;
         }
        
        visited[sv-1]=1;
        unvisited[sv-1]=0;
        int ind=0,src=0;
        int tc=0,count=1;
        //*****************
        for(int i=1;i<num;i++)
        {
            int min=99;
            for(int j=0;j<num;j++)
            {
                if(visited[j]==1)
                {
                    for(int k=0;k<num;k++)
                    {
                       if((unvisited[k]==1)&&(CM[j][k]!=999)) 
                       {
                           if(CM[j][k]<min)
                           {
                               min=CM[j][k];
                                src=j;
                                ind=k;
                           }
                       }
                    }
                }
            }
            visited[ind]=1;
            unvisited[ind]=0;
            
            System.out.println((count++)+" edge is"+" "+(src+1)+"--->"+(ind+1));
            tc=tc+min;
        }
        System.out.println("The total cost spent is "+tc);
        
    }
}

public class Hehe {
    
    
    public static void main(String[] args)throws Exception {
        Scanner sc=new Scanner(System.in);
        int n;
        System.out.println("Enter the number of vertices");
        n=sc.nextInt();
        if(n==0 || n<0)
        {
            throw new excep();
        }
        int j,i;
        int CM[][]=new int[n][n];
        System.out.println("Enter the adjacency matrix of size "+n+"x"+n);
        
        for(i=0;i<n;i++)
        {
            for(j=0;j<n;j++)
            {
                CM[i][j]=sc.nextInt();
            }
        }
        System.out.println("The entered adjacency matrix is");
        for(int x[]:CM)
        {
            for(int y:x)
            {
                System.out.print(y+"  ");
            }
            System.out.println();
        }
        
        solveprims.primsmeth(n,CM);
        
      
    }// main
}