Question

I’m trying to do a program with matrix. In four numbers, only the first less 1. When the first matrix finish, just the second matris less 1. And goes by to the end. The 0 number is not allowed.

For example, when I run the code, need to return this:

[2][1][3][3]
[1][1][3][3]
[1][3][3]
[3][3]
[2][3]
[1][3]
[3]
[2]
[1]

But that is not happening with this code:

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

int main()
{
    int fila[4], var;

    for (var=0;var<4;var++) {
        fila[var]=0;
        srand(rand());
        fila[var]=rand()%3+1;
        printf("[%d]",fila[var]);
        fila[0]=fila[0]-1;
    }
    system("pause>NULL");


    while(fila[0]>0)
    {
        printf("[%d][%d][%d][%d]\n",fila[0],fila[1],fila[2],fila[3]);
        fila[0]--;
        system("pause");
    }

    fila[1]=fila[1]-1;

    while(fila[1]>0)
    {
        printf("[%d][%d][%d]\n",fila[1],fila[2],fila[3]);
        fila[1]--;
        system("pause");
    }

    fila[2]=fila[2]-1;

    while(fila[2]>0)
    {
        printf("[%d][%d]\n",fila[2],fila[3]);
        fila[2]--;
        system("pause");
    }

    fila[3]=fila[3]-1;

    while(fila[3]>0)
    {
        printf("[%d]\n",fila[3]);
        fila[3]--;
        system("pause");
    }

    return 0;
}

What I’m missing?
Thanks.

That code prints:

[2][1][2][1]
[1][1]

Answer 1

You need two nested loops to do it:

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

int main(void) {
    int fila[4], i, j;
    srand(rand());
    for (i=0;i != 4; i++) {
        fila[i]=rand()%3+1;
    }
    for (i=0 ; i != 4 ; fila[i]--, i += (fila[i] == 0)) {
        for (j = i ; j != 4 ; j++) {
            printf("[%d] ", fila[j]);
        }
        printf("\n");
    }
    return 0;
}

The outer loop iterates until you get to the end of fila; inner loop prints the remaining elements of fila starting at the index of i.

Note that you shouldn’t be re-seeding srand in a loop – you do it only once before the loop.

Here is the link to this program on ideone.