Vector within array?

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Vector within array?

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#1 by (1 votes)
#2 by (0 votes)

0

My function needs to find the line on which the first occurrence of a vector within a matrix occurs and return its line. But is always returning the wrong line, my logic is wrong?

My role:

int busca( int mat[][MAX],int n, int m, int N, float vetor[])
{  
int i,j,k,aux;

for(k=0;k<N;k++)
{
    printf("Informe o valor do %d vetor:", k+1  ); // le o vetor
    scanf("%f",&vetor[k]);
}

for (i =0; i < n ;i ++)
{
    for ( j = 0; j < m ;j ++)
    {
        printf ("Digite mat [%d][%d]: ",i , j) ; //le a matriz
        scanf ("%d",&mat [i][j]) ;
    }
}

//aqui seria a logica pra achar o elemento igual
for(i=0; i<n;i++)
{
    for(j=0;j<m;j++)
    {
        if(mat[i][j] == vetor[k])
        {
            return i;

        }
    }
}

if (i>=0)  
printf("  A primeira ocorrencia do vetor eh na linha %d\n.",i-1 );
else
return -1;
}

c

asked by anonymous 23.06.2018 / 17:41

2 answers

0

Your logic is wrong. I did not test the code but what its function does is to return the first line containing the last element of the vector. A good alternative would be to do the following:

//aqui seria a logica pra achar o elemento igual
for(i == 0; i < n; i++){
    if(!memcmp(mat[n], vector, sizeof(vector));
        return i;
}

return -1

The function memcmp compares two blocks of code and returns 0 if the blocks are equal.

24.06.2018 / 17:43

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score 1 · Accepted Answer

Your logic to find the vector is incomplete, because you need to zero the k variable, which was previously used in this part of the code:

for(k=0;k<N;k++)
{
    printf("Informe o valor do %d vetor:", k+1  ); // le o vetor
    scanf("%f",&vetor[k]);
}

So a solution, using its logic still, would be as follows:

// essa variável deve ser utilizada antes da repetição
int cont;

///aqui seria a logica pra achar o elemento igual
for(i=0; i<n;i++)
{
    cont=0;
    k = 0;

    for(j=0;j<m;j++, k++)
    {
        //essa condição serve para caso o "k" ultrapasse o tamanho
        // "N" do vetor, evitando acessar um índice do vetor que
        // não existe
        if(k>=N)
        {
            k=0;
        }

        if(mat[i][j] == vetor[k])
        {
            // aqui a variável conta quantos elementos do vetor 
            // são iguais a linha "i" da matriz
            cont++; 
        }
    }

    // se "cont" for igual a quantidade "N" de elementos do vetor
    // isso quer dizer que o programa encontrou a primeira ocorrência
    // do vetor na matriz 
    if(cont == N)
    {
        break;
    }
}

The result display should also be corrected for the following:

    if (i>=0 && cont == N) 
        // Tem que ser utilizado "i" e não "i-1", pois caso o "i"
        // seja igual a zero, será exibido -1
        printf("  A primeira ocorrencia do vetor eh na linha %d\n.",i );
    else
        return -1;

I hope I have helped.