View Compilation Error

0_0_16265023_21881.cpp: In function 'int main()':
0_0_16265023_21881.cpp:16:9: error: '_int64' was not declared in this scope
         _int64 sum=0;
         ^
0_0_16265023_21881.cpp:20:13: error: 'sum' was not declared in this scope
             sum=sum+b[i];
             ^