const int DAYS=7; // Global constants
const int TIME=5;
// function prototypes
void getInfile( double [DAYS][TIME]);
int dayRelease(double [DAYS][TIME], int);
void avgDistance(double [][TIME]);
int maxDistance(double [][TIME], int);
void printHeading(string[]);
double distance[DAYS][TIME]; // 2D array for storing the distance values
int day; // row subscript for distance array
int time; // column subscript for distance array
int max; // subscript for the largest distance in a row
Those two functions have no definition; either they've never been written, or they've been written but not compiled, or they've been compiled but you're not linking to the compiled object containing them.