prim algorithm c++ for powergrid code example

Example 1: c program for prims algorithm

#include<stdio.h>
#include<conio.h>
int a,b,u,v,n,i,j,ne=1;
int visited[10]= {	0},min,mincost=0,cost[10][10];
void main() {	
clrscr();	
printf("\n Enter the number of nodes:");	
scanf("%d",&n);	
printf("\n Enter the adjacency matrix:\n");	
for (i=1;i<=n;i++)	  
    for (j=1;j<=n;j++) {		
      scanf("%d",&cost[i][j]);		
      if(cost[i][j]==0)		    
      cost[i][j]=999;	
      }	
    visited[1]=1;	
    printf("\n");	
    while(ne<n) {		
      for (i=1,min=999;i<=n;i++)		  
        for (j=1;j<=n;j++)		    
          if(cost[i][j]<min)		     
          if(visited[i]!=0) {			
          min=cost[i][j];			
          a=u=i;			
          b=v=j;		
          }		
          if(visited[u]==0 || visited[v]==0) 
          {			
            printf("\n Edge %d:(%d %d) cost:%d",ne++,a,b,min);
            mincost+=min;			
            visited[b]=1;		
            }		
          cost[a][b]=cost[b][a]=999;	
          }	
          printf("\n Minimun cost=%d",mincost);
          getch();
}

Example 2: prims c++

#include <iostream>
#include <vector>
#include <queue>
#include <functional>
#include <utility>

using namespace std;
const int MAX = 1e4 + 5;
typedef pair<long long, int> PII;
bool marked[MAX];
vector <PII> adj[MAX];

long long prim(int x)
{
    priority_queue<PII, vector<PII>, greater<PII> > Q;
    int y;
    long long minimumCost = 0;
    PII p;
    Q.push(make_pair(0, x));
    while(!Q.empty())
    {
        // Select the edge with minimum weight
        p = Q.top();
        Q.pop();
        x = p.second;
        // Checking for cycle
        if(marked[x] == true)
            continue;
        minimumCost += p.first;
        marked[x] = true;
        for(int i = 0;i < adj[x].size();++i)
        {
            y = adj[x][i].second;
            if(marked[y] == false)
                Q.push(adj[x][i]);
        }
    }
    return minimumCost;
}

int main()
{
    int nodes, edges, x, y;
    long long weight, minimumCost;
    cin >> nodes >> edges;
    for(int i = 0;i < edges;++i)
    {
        cin >> x >> y >> weight;
        adj[x].push_back(make_pair(weight, y));
        adj[y].push_back(make_pair(weight, x));
    }
    // Selecting 1 as the starting node
    minimumCost = prim(1);
    cout << minimumCost << endl;
    return 0;
}