View Compilation Error

0_0_4886095_16557.c: In function `main':
0_0_4886095_16557.c:7: error: `NULL' undeclared (first use in this function)
0_0_4886095_16557.c:7: error: (Each undeclared identifier is reported only once
0_0_4886095_16557.c:7: error: for each function it appears in.)
0_0_4886095_16557.c:16: error: `MAX' undeclared (first use in this function)
0_0_4886095_16557.c:25: error: `DOWN' undeclared (first use in this function)
0_0_4886095_16557.c:25: error: `UP' undeclared (first use in this function)