View Compilation Error

0_0_17254179_23298.cpp: In function 'int main()':
0_0_17254179_23298.cpp:13:3: error: '_int64' was not declared in this scope
   _int64 sum=0;   
   ^
0_0_17254179_23298.cpp:21:5: error: 'sum' was not declared in this scope
     sum+=a[i];
     ^
0_0_17254179_23298.cpp:23:4: error: 'sum' was not declared in this scope
    sum=sum-max1+1;
    ^