View Compilation Error

0_0_31120906_14207.cpp: In function 'int main(int, const char**)':
0_0_31120906_14207.cpp:5:5: error: '__int64_t' was not declared in this scope
     __int64_t arr[51];
     ^
0_0_31120906_14207.cpp:7:5: error: 'arr' was not declared in this scope
     arr[0]=1;arr[1]=2;
     ^