View Compilation Error

0_0_1230671_26125.cpp: In function `int main()':
0_0_1230671_26125.cpp:5: error: `_int64' undeclared (first use this function)
0_0_1230671_26125.cpp:5: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_1230671_26125.cpp:5: error: expected `;' before "num"
0_0_1230671_26125.cpp:6: error: `num' undeclared (first use this function)