View Compilation Error

0_0_9171616_6459.c:7: error: syntax error before "vis"
0_0_9171616_6459.c: In function `solve':
0_0_9171616_6459.c:12: error: `false' undeclared (first use in this function)
0_0_9171616_6459.c:12: error: (Each undeclared identifier is reported only once
0_0_9171616_6459.c:12: error: for each function it appears in.)
0_0_9171616_6459.c:38: error: `true' undeclared (first use in this function)