View Compilation Error

0_0_5927759_1890.cpp: In function `int main()':
0_0_5927759_1890.cpp:3: error: `_int64' undeclared (first use this function)
0_0_5927759_1890.cpp:3: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_5927759_1890.cpp:3: error: expected `;' before "n"
0_0_5927759_1890.cpp:4: error: `a' undeclared (first use this function)
0_0_5927759_1890.cpp:7: error: `n' undeclared (first use this function)
0_0_5927759_1890.cpp:8: error: `i' undeclared (first use this function)