View Compilation Error

0_0_1509162_15220.cpp: In function `int main()':
0_0_1509162_15220.cpp:120: error: `OPEN' undeclared (first use this function)
0_0_1509162_15220.cpp:120: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1509162_15220.cpp:120: error: expected `;' before "scanf"