View Compilation Error

0_0_8568103_9249.c: In function `main':
0_0_8568103_9249.c:13: error: `stack' undeclared (first use in this function)
0_0_8568103_9249.c:13: error: (Each undeclared identifier is reported only once
0_0_8568103_9249.c:13: error: for each function it appears in.)
0_0_8568103_9249.c:13: error: syntax error before "s"
0_0_8568103_9249.c:17: error: `s' undeclared (first use in this function)