View Compilation Error

0_0_21656722_1265.cpp:5:1: error: '_int64' does not name a type
 _int64 mod = 2147483647;
 ^
0_0_21656722_1265.cpp:6:1: error: '_int64' does not name a type
 _int64 a[105];
 ^
0_0_21656722_1265.cpp: In function 'int main()':
0_0_21656722_1265.cpp:19:20: error: 'a' was not declared in this scope
    scanf("%I64d", &a[i]);
                    ^
0_0_21656722_1265.cpp:21:8: error: 'a' was not declared in this scope
   sort(a + 1, a + n + 1);  //排序
        ^
0_0_21656722_1265.cpp:43:24: error: 'mod' was not declared in this scope
    if ((a[l] + a[i]) % mod == a[r])
                        ^