Dijkstra's Shortest Path Algorithm issue

Question

So I'm trying to code Dijkstra's shortest path algorithm in C++. For some reason, it's not adding up the distances correctly...

Here is what I have so far for code. You can ignore the section where I am copying the path to the stack because I know it's not complete yet. Any ideas where I'm going wrong?

#include <fstream>
#include "matrix.h"
#include <list>     // STL container
using namespace std;
//---------------------------------------------------------------------------

const int INFIN = 100000;
const int size = 8;

double a[] = {
        0, 0, 5, 0, 0, 2, 3, 0,     //length matrix ( #9, page 276)
        4, 0, 6, 0, 7, 0, 5, 0,
        0, 3, 0, 9, 2, 6, 0, 7,
        3, 0, 2, 0, 1, 0, 7, 6,
        0, 5, 0, 1, 0, 0, 4, 0,
        0, 0, 2, 0, 8, 0, 9, 0,
        1, 2, 3, 0, 0, 6, 0, 0,
        5, 0, 8, 0, 2, 0, 9, 0
    };

        //  Global declarations for L Matrix and begin and end node

Matrix L(size,size,a);          //length matrix
int begin, end;

void path(long* D, int* P);     //function prototype for shortest path algorithm

Matrix Warshall(Matrix M);

void main()
{
    int i, u;
    long D [size+1];            //distance functions
    int P [size+1];             //prior vertices in path

    cout << "\nLength Matrix: " << L;
    cout << "\nPaths that exist:" << Warshall(L);

    for (i=1; i <= size; i++)  {
        D[i] = INFIN;           //initialize distance functions
        P[i] = 0;
}


cout << "\nFind distance from vertex #";
cin >> begin;
cout <<   "                to vertex #";
cin >> end;

if (begin == end) exit(1);
if (begin < 0 || end < 0) exit(1);
if (begin > size || end > size) exit(1);

path(D,P);

cout  << "\nShortest distance from \nvertex #"
     << begin << " to vertex #"
     << end << " is " << D[end];

// u = end;
list<int> stack;            // work path backwards
while (1) {
    stack.push_front(end);
    stack.push_front(begin);
    break;
    }

    cout    << "\nusing path:\n";
    cout << "\t" << stack.front();
    stack.pop_front();
    while (stack.size()) {
        cout << " -> " << stack.front();
        stack.pop_front();
    }
    getch();
}

void path(long* D, int* P) {
    int i, u, dist;
    int U[size+1];
    for (i=1; i <= size; i++)
    U[i] = 0;
    U[begin] = 1;                                       // add first vertex;
    D[begin] = 0;
    u = begin;
    do {                            // until find end vertex
        for (i = 1; i <= size; i++)  {
        dist = L.element(u,i);          // distance from u to i
        if( D[u] + dist < D[i]) {
            D[i] = D[u] + dist;
            P[i] = u;
            }
   }
        dist = 38000;           // reset distance value to large value
        int min;
        for(i = 1; i <= size; i++) {
    if(L.element(u,i) != 0) {
            if(L.element(u,i) < dist && U[i] != 1) {
                dist = L.element(u,i);
                min = i;
            }
        }
    }
    u = min;
    U[u] = 1;
    cout << "Min is " << min << endl;
    } while (u != end);
}            

Answer 1

if( D[u] + dist < D[i]) {
            D[i] = D[u] + dist;
            P[i] = u;


}

should be

if( D[u] + dist < D[i] && dist != 0) {
            D[i] = D[u] + dist;
            P[i] = u;


}