View Compilation Error

0_0_21027027_13151.cpp:10:1: error: '_int64' does not name a type
 _int64 s1[55];
 ^
0_0_21027027_13151.cpp: In function 'int main()':
0_0_21027027_13151.cpp:18:17: error: 's1' was not declared in this scope
    scanf("%d", &s1[i]);
                 ^
0_0_21027027_13151.cpp:24:5: error: 's1' was not declared in this scope
     s1[j] = s1[j] + s1[i];
     ^
0_0_21027027_13151.cpp:27:3: error: '_int64' was not declared in this scope
   _int64 sum = 0;
   ^
0_0_21027027_13151.cpp:30:4: error: 'sum' was not declared in this scope
    sum = sum + s1[i];
    ^
0_0_21027027_13151.cpp:30:16: error: 's1' was not declared in this scope
    sum = sum + s1[i];
                ^
0_0_21027027_13151.cpp:32:21: error: 'sum' was not declared in this scope
   printf("%I64d\n", sum);
                     ^