[help] DFS, cant find my mistake...

[Fromar123]

I have a DFS algorithm here, and when i run the thing and try to find the path, my console stops responding (it crashes), so i would like to ask if anyone can tell me what is wrong?? -I worked on this for hours but cant identify the problem.

#include<iostream>
#include<fstream>
#include <stack>

using namespace std;


void menu(){
     cout << "DFS " << endl;
     cout << "1) Read graph from file" << endl;
     cout << "2) Search: s - d " << endl;     
     cout << "3) EXIT" << endl << endl;
}



struct Vert{
       int name;
       int elder;
       int depth;
       int status;       
};

int size;
int C[30][30];

void read(string f){
  fstream dat(f.c_str(), fstream::in);
  dat >> size;
  int i=0;
  int p, q, c;

  while(!dat.eof())
  {
    dat >> p >> q >> c;
	C[p-1][q-1] = c;
	C[q-1][p-1] = c;
    i++;
  }
  dat.close();
}



int top;
int stacks[30];

void PUSH(int v){
     stacks[top]=v;
     top++;     
}

int POP(int a){
    top--;
    stacks[top]=a;
    return stacks[top];    
}


void DEPTH_SEARCH(int C[30][30], int vel, int s){

     Vert V[30]; 
     
     for(int x=0; x<vel; x++){
             V[s].name=x;
             V[s].depth=99999;
             V[s].elder=-1;
             V[s].status=1;
     }
     s[V].depth=0;
     s[V].elder=-1;
     s[V].status=1;
     
     PUSH(s);
     
     int v;
     while(!(top==0)){
           POP(v);
           
           for(int i=0; i<vel; i++){
                   if(C[v][i] == s  && V[i].status == 0){
                              V[i].depth=V[v].depth+1;
                              V[i].elder=v;
                              V[i].status=1;
                              PUSH(i);
                   }
                   V[v].status=2;   
           }           
     }
       

          
}

void PRINT_PATH(Vert V[30], int s, int d){
     if(s==d){
              cout << "Vert: " << s << ", depth: " << V[s].depth << endl;
                       
     }else{
           if(V[d].elder==-1){
                   cout << "No path. " << endl;                        
           }      
           else{
                PRINT_PATH(V,s,V[d].elder);
                cout << "Vert: " << d << ", depth: " << V[d].depth << endl;     
           }
           
     }
}


int main(){

    int select;
    int s;
    int d;
    int vel;
    Vert V[30];
    
    
    
    do{
         menu();
         cout << "Selection: ";
         cin >> select;
         cout << endl;
         
         switch(select){
                case 1:
                      read("graph.txt");
                      cout << "size: " << size << endl;
                      for(int j=0;j<size;j++){
	                      for(int i=0;i<size;i++){
	                         cout << C[i][j] << " ";
                          }
                          cout << endl;
                       }
                       cout << endl;
                     break;
                     
                case 2:
                     cout << "Enter s: ";
                     cin >> s;
                     cout << endl;
                     cout << "Enter d: ";
                     cin >> d;
                     cout << endl;
                     DEPTH_SEARCH(C, vel, s);
                     PRINT_PATH(V, s, d);
                     break;
                     
                case 3:
                     break;               
         }
         
    }while(select!=3);
   
    system("PAUSE");
    return 0;    
}

[jyU4izwU]

Try

using namespace std;


void menu(void)
{
     cout << "DFS " << endl;
     cout << "1) Read graph from file" << endl;
     cout << "2) Search: s - d " << endl;     
     cout << "3) EXIT" << endl << endl;
}

[Fromar123]

no, doesnt work, still gives: '...stopped working' and my programme crashes...

It runs fine, but when i press 2, to call the DEPTH_SEARCH function, it crashes...

[ne555]

_ Uninitialized variables
_ Bad reading (that may cause invalid access). Don't loop on eof

Provide an example run.
Also, perform a backtrace when it crashes