View Compilation Error

0_0_36688227_11027.cpp:3:25: error: expected unqualified-id before '.' token
 const int maxn = 5e6+10;.
                         ^
0_0_36688227_11027.cpp: In function 'int main()':
0_0_36688227_11027.cpp:7:18: error: 'n' was not declared in this scope
     scanf("%d", &n);
                  ^
0_0_36688227_11027.cpp:8:5: error: 'p1' was not declared in this scope
     p1 = 1, p2 = 2;
     ^
0_0_36688227_11027.cpp:8:13: error: 'p2' was not declared in this scope
     p1 = 1, p2 = 2;
             ^
0_0_36688227_11027.cpp:12:13: error: 'a' was not declared in this scope
             a[x] = 1;
             ^