Reading a Matrix txt file and storing as an array

Question

I\'m currently writing a Simulated Annealing code to solve a traveling salesman problem and have run into difficulties with storing and using my read data from a txt file. E

Answer 1

Here is how I would load/save it:

#include 
#include 
#include 

int width = 0;
int height = 0;
double **distances;

void WriteDouble( std::ofstream &stream, double toWrite )
{
    char buffer[8];
    memcpy( buffer, &toWrite, 8 );
    stream.write( buffer, 8 );
}

void WriteInt( std::ofstream &stream, int toWrite )
{
    char buffer[4];
    memcpy( buffer, &toWrite, 4 );
    stream.write( buffer, 4 );
}

double ReadDouble( std::ifstream &stream )
{
    double d = 0;
    stream.read( (char *)&d, 8 );
    return d;
}

int ReadInt( std::ifstream &stream )
{
    int i = 0;
    stream.read( (char *)&i, 4 );
    return i;
}

void Save()
{
    std::ofstream stream( "cities", std::ios::out | std::ios::binary );

    if( !stream.good() ) {
        throw std::exception( "Error opening stream" );
    }

    WriteInt( stream, width );
    WriteInt( stream, height );

    for( int x = 0; x < width; x++ ) {
        for( int y = 0; y < height; y++ ) {
            WriteDouble( stream, distances[x][y] );
        }
    }

    stream.close();
}

void Load()
{
    std::ifstream stream( "cities", std::ios::in | std::ios::binary );

    if( !stream.good() ) {
        throw std::exception( "Error opening stream" );
    }

    width = ReadInt( stream );
    height = ReadInt( stream );

    distances = new double *[width];

    for( int i = 0; i < width; i++ ) {
        distances[i] = new double[height];
    }

    for( int x = 0; x < width; x++ ) {
        for( int y = 0; y < height; y++ ) {
            distances[x][y] = ReadDouble( stream );
        }
    }

    stream.close();
}

void RunSaveTest()
{
    width = 15;
    height = 15;

    distances = new double *[width];

    for( int i = 0; i < width; i++ ) {
        distances[i] = new double[height];
    }

    for( int x = 0; x < width; x++ ) {
        for( int y = 0; y < height; y++ ) {
            distances[x][y] = (double)x / (double)( y + 1 );
            std::cout << distances[x][y] << std::endl;
        }
    }

    Save();
}

void RunLoadTest()
{
    Load();

    for( int x = 0; x < width; x++ ) {
        for( int y = 0; y < height; y++ ) {
            std::cout << distances[x][y] << std::endl;
        }
    }
}

int main()
{
    RunSaveTest();
    // RunLoadTest();

    return 0;
}