// Program 8.13

#include<stdio.h>

int main( void )
{

    void scalarMultiply( int matrix[3][5], int scalar );
    void displayMatrix( int matrix[3][5] );
    int sampleMatrix[3][5] =
    {
	{ 7, 16, 55, 13, 12 },
	{ 12, 10, 52, 0, 7 },
	{ -2, 1, 2, 4, 9 }
    };

    printf( "Original matrix:\n" );
    displayMatrix( sampleMatrix );

    scalarMultiply( sampleMatrix, 2 );

    printf( "\nMultiplied by 2:\n" );
    displayMatrix( sampleMatrix );

    scalarMultiply( sampleMatrix, -1 );

    printf( "\nThen multiplied by -1:\n" );
    displayMatrix( sampleMatrix );

    return 0;

}

// Function to multiply a 3 x 5 array by a scalar

void scalarMultiply( int matrix[3][5], int scalar )
{

    int row, column;

    for( row = 0; row < 3; ++row )
	for( column = 0; column < 5; ++column )
	    matrix[row][column] *= scalar;

}

void displayMatrix( int matrix[3][5] )
{

    int row, column;

    for( row = 0; row < 3; ++row )
    {
	
	for( column = 0; column < 5; ++ column )
	    printf( "%5i", matrix[row][column] );

	printf( "\n" );

    }

}
