View Compilation Error

0_0_36176649_12.cpp:6:1: error: expected initializer before 'struct'
 struct node{
 ^
0_0_36176649_12.cpp:10:2: error: 'a' does not name a type
 }a[maxn+2];
  ^
0_0_36176649_12.cpp: In function 'int main()':
0_0_36176649_12.cpp:20:4: error: 'a' was not declared in this scope
    a[i].p=l/r;
    ^
0_0_36176649_12.cpp:25:4: error: 'dp' was not declared in this scope
    dp[i]=0;
    ^
0_0_36176649_12.cpp:27:13: error: 'a' was not declared in this scope
    double p=a[i].p;
             ^
0_0_36176649_12.cpp:30:29: error: 'dp' was not declared in this scope
    long long tmp=(1.0-p)/p*(dp[i-1]-dp[x]+v);
                             ^
0_0_36176649_12.cpp:36:11: error: 'dp' was not declared in this scope
    cout<<(dp[b]-dp[a])%mod<<endl;
           ^