Algorithm that searches a value in an 2 dimensional array (matrix).

general
1

Searching a value in an 2 dimensional array (matrix).

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2

#include
#include
#include

int main()
{
const size_t N = 3;
int a[N][N] =
{
{ 1, 2, 3 },
{ 4, 5, 6 },
{ 7, 8, 9 }
};

int value = 9;

auto it = std::find( reinterpret_cast<int *>( a ),
                     reinterpret_cast<int *>( a ) + N * N,
                     value );

if ( it != reinterpret_cast<int *>( a ) + N * N )
{
    size_t n = std::distance( reinterpret_cast<int *>( a ), 
                              it );
    std::cout << "Row = " << n / N << ", Column = " << n % N << std::endl;
}

size_t row = 0;
size_t col = 0;

for ( ; row < N; row++ )
{
    col = 0;
    while ( col < N && a[row][col] != value ) col++;
    if ( col != N ) break;
}

if ( row != N )
{
    std::cout << "Row = " << row << ", Column = " << col << std::endl;
}

return 0;

}

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3

I think it is good tutorial for solving this problem.

1 Like