Below is one solution to solve the Dining Philosopher problem based on monitor and conditional variable. Please use one example to trace its execution. #define N enum status (EATING, HUNGRY, THINKING); monitor dining Philosophers { status state [N]; condition self [N]; test (int i) { if ((state [(i-1) mod N] != EATING) && (state [i] HUNGRY) && (state [(i+1) mod N] != EATING)) { state [i] EATING; self [i].signal (); } }; public: dining Philosophers () { // Initilization. for (int i = 0; i < N; i++) state[i] = THINKING; }; test (int i) { if ((state [ (i-1) mod N] != EATING) && (state[i] == HUNGRY) && (state (i+1) mod N] != EATING)) { state[i] EATING; self [i].signal(); }; }; public: dining Philosophers () {...}; OpickUpForks (int i) { }; state [i] = HUNGRY; test (i); if (state[i] != EATING) self [i].wait(); put DownForks (int i) { state [i] THINKING; test ((i-1) mod N); test ((i+1) mod N); }; }