error C2109: subscript requires array or pointer type

#include <stdio.h>
#include <iostream>

using namespace std;

    int main(void)
    {
bool premiereLignefaite = false;
//Lire le fichier
FILE * graphe = fopen("graphe.txt", "r");
//Fichier de sortie
FILE * resultat = fopen("resultat.txt", "w");
int nbr1, nbr2;
int *matrice; //pointeur vers la matrice d'adjacence

//Ligne lue
static char ligne[50];

while (fgets(ligne, 50, graphe) != NULL) //retourne 0 quand on a end-of-file
{
    //La premiere ligne est différente
    if (premiereLignefaite == false) {
        //Initialiser une matrice d'adjacence NxN
        sscanf(ligne, "%d %d", &nbr1, &nbr2);
        matrice =  new int(nbr1 * nbr1); //Memoire dynamique pour la matrice dadjac开发者_StackOverflow中文版ence n x n
        premiereLignefaite = true;
        continue;
    }
    //On construit notre matrice d'adjacence
    sscanf(ligne, "%d %d", &nbr1, &nbr2);
    matrice[nbr1][nbr2] = 1;
}

int u = 2+2;


return 0;
 }

So I'm getting an error on this line : matrice[nbr1][nbr2] = 1; I'm just trying to build an adjacency list from a text file. I don't understand what I'm doing wrong. Thank you.

EDIT: Since people ask about it, this is my graph file. The first line is the number of vertices and the number of edges(not useful imo) The following lines are my edges, I use the first line to allocate memory for a NxN graph and the following lines to fill in my adjacency matrix.

9 20
0 1
0 2
1 0
1 2
1 3
1 5
2 0
2 1
2 3
3 1
3 2
3 4
4 3
5 1
5 6
5 7
6 5
6 8
7 5
8 6

---

int *matrice; means that matrice is a pointer to an int (or ints), so matrice[a] will give you an int. A pointer does not have any information about the dimensions of the array, so you can't do two-dimensional access.

You want to do store the dimensions of your array and then do

matrice[nbr1 * numberOfColumns + nbr2] = 1;

Side notes:

• Raw array access via pointers can be VERY dangerous if you're not careful with bounds checking. Consider std::vector<>.
• You probably meant new int[nbr1 * nbr2]?

---

matrice[x] is the same thing as *(matrice+x), and matrice[x][y] is the same thing as *(*(matrice+x)+y).

So the problem is that when you write matrice[nbr1][nbr2], that's the same as writing *(*(matrice+nbr1)+nbr2). Since matrice is only a pointer, and not a pointer to a pointer, this of course doesn't work.

---

matrice declared as int * which makes it a signle-dimensional array. It could not be accessed as multidimensional array matrice[nbr1][nbr2]. Also check your memory allocations code. It should be new int[nbr1 * nbr2], not new int(nbr1 * nbr2).