kruskal algorithm implementation

Question

i have following code from graph theory topics,kruskal algorithm for minimal spanning tree

#include<iostream>
#include<stdlib.h>
using namespace std;
int cost[10][10],i,j,k,n,m,c,visit,visited[10],l,v,count,count1,vst,p;
int main(){
    int dup1,dup2;
    cout<<" enter number of vertices "<<endl;
    cin>>n;
    cout<<"enter number of edges "<<endl;
    cin>>m;
    cout<<" EDGES  Cost "<<endl;
    for(k=1;k<=m;k++){
        cin>>i>>j>>c;
        cost[i][j]=c;
        cost[j][i]=c;

    }
    for(i=1;i<=n;i++)

        for(j=1;j<=m;j++)

            if(cost[i][j]==0)
                cost[i][j]=31999;
            visit=1;
            while(visit<n){
                v=31999;
                for(i=1;i<=n;i++)
                    for(j=1;j<=n;j++)
    if(cost[i][j]!=31999 && cost[i][j]<v && cost[i][j]!=-1)
    {
        int count=0;
        for(p=1;p<=n;p++){


            if(visited[p]==i || visited[p]==j)
                count++;
        }
        if(count>=2){

            for(p=1;p<=n;p++)
                if(cost[i][p]!=31999 && p!=j)
                    dup1=p;
             for(p=1;p<=n;p++)
                 if(cost[j][p]!=31999 && p!=i)
                     dup2=p;
            if(cost[dup1][dup2]==-1)
                continue;
        }
         l=i;
         k=j;
         v=cost[i][j];

        }

        cout<<" edgde from "<<l<<" --> "<<k;
        cost[l][k]=-1;
        cost[k][l]=-1;
        visit++;
        int count=0;
        count1=0;
        for(i=1;i<=n;i++)
        {

            if(visited[i]==1)
                count++;
            if(visited[i]==k)
                count1++;

        }
        if(count==0)
            visited[++vst]=1;
         if(count1==0)
             visited[++vst]=k;

        }


return 0;
}

which works and for following input

1 2 1
2 3 2
3 4 3
1 3 3

where number of vertices and number of edges is 4,gives me output like this

edge from 1–>2edge from 2–>3edge from 1–>3

my question is is there any semantical error?also i have used arrays and many variables,can i make shorted this code?my (programming)language is c++

Answer 1

User input can easily break this code: If the user gives values equal to or greater than 10 for n or m, you could run off the end of your array.