Write a main function together with a collection of functions that operates on a twodimensional matrix (a global variable) with ROW_SIZE rows and COL_SIZE columns. The
main function should provide calls to each of the functions and display the results. The
functions should have the following declarations:
void set_row(int row, double[] row_vals); // Stores the array of
// row_vals in row
double* get_row(int row); // Returns the specified row
void set_element(int row, int col, int val); // Sets the specified
// element
double get_element(int row, int col); // Returns the specified element
double sum(); // Returns sum of the values in the array
double find_max(); // Returns the largest value in the array
double find_min(); // Returns the smallest value in the array
string to_string(); // Returns a string representing the matrix