Loop does not perform everything it should

Question

I have a problem in my program, I need it to show randomly an order of numbers (teams). The problem is that when I put a number greater than 10 it doesn’t show the 10, it only shows a few:

   int cont1, aux, n, sorteio;
    char op = 's';



setlocale(LC_ALL, "portuguese");

do{
    printf("Digite a quintidade de equipes para serem sorteadas: ");
    scanf("%d", &n);
    printf("\n--------------------------------------------------------------------------------------------\n\n");

    int matriz[2][n];

    for(cont1 = 0; cont1 < n; cont1++){
        matriz[1][cont1] = cont1 + 1;
        matriz[2][cont1] = cont1 + 1;
    }

    srand(time(NULL));

    for(cont1 = 0; cont1 < n; cont1++){
        sorteio = rand() % n;
        aux = matriz[2][cont1];
        matriz[2][cont1] = matriz[2][sorteio];
        matriz[2][sorteio] = aux;

    }

    for(cont1 = 0; cont1 < n; cont1++){
        printf("Linha 1 da MATRIZ - Ordem das Apresentações: %d   |   ", matriz[1][cont1]);
        printf("Linha 2 da MATRIZ - Número da Equipe: %d", matriz[2][cont1]);
        printf("\n");

    }
    printf("\n--------------------------------------------------------------------------------------------\n\n");
    printf("Deseja realizar outro sorteio? (S/N)> ");

    fflush(stdin);

    op = getchar();

    fflush(stdin);

    printf("\n--------------------------------------------------------------------------------------------\n\n");

}while((op == 'S') | (op == 's'));

}

Answer 1

The problem is access to array. You are accessing index 1 and 2 of array, ma it only goes up to index 1. arrays start at 0. Note that in the column you are doing it right, since the loop starts at 0, but in the line it is starting at 1, so one of the dimensions is not being initialized, and this is no problem, because it is never accessed anyway, but when you try to write in index 2 that has no memory reserved for it ends up passing over other areas of memory reserved for something else and then the control number, in case n ends up being changed unintentionally. So it is correct and more organized (can improve more):

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(void) {
    int n;
    char op = 's';
    do {
        printf("Digite a quantidade de equipes para serem sorteadas: ");
        scanf("%d", &n);
        printf("\n--------------------------------------------------------------------------------------------\n");
        int matriz[2][n];
        for (int cont1 = 0; cont1 < n; cont1++) {
            matriz[0][cont1] = cont1 + 1;
            matriz[1][cont1] = cont1 + 1;
        }
        srand(time(NULL));
        for (int cont1 = 0; cont1 < n; cont1++) {
            int sorteio = rand() % n;
            int aux = matriz[1][cont1];
            matriz[1][cont1] = matriz[1][sorteio];
            matriz[1][sorteio] = aux;
        }
        for (int cont1 = 0; cont1 < n; cont1++) {
            printf("Linha 1 da MATRIZ - Ordem das Apresentações: %d   |   ", matriz[0][cont1]);
            printf("Linha 2 da MATRIZ - Número da Equipe: %d\n", matriz[1][cont1]);
        }
        printf("\n--------------------------------------------------------------------------------------------\n\n");
        printf("Deseja realizar outro sorteio? (S/N)> ");
        op = getchar();
        printf("\n--------------------------------------------------------------------------------------------\n\n");
    } while (op == 'S' || op == 's');
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.