View Compilation Error

0_0_4209099_27062.cpp: In function `int main()':
0_0_4209099_27062.cpp:6: error: `_int64' undeclared (first use this function)
0_0_4209099_27062.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4209099_27062.cpp:6: error: expected `;' before "i"
0_0_4209099_27062.cpp:9: error: `sum' undeclared (first use this function)
0_0_4209099_27062.cpp:12: error: `i' undeclared (first use this function)
0_0_4209099_27062.cpp:16: error: `s' undeclared (first use this function)