View Compilation Error

0_0_32427792_27283.cpp: In function 'int main()':
0_0_32427792_27283.cpp:12:7: error: expected ';' before 'a'
  node a[M];
       ^
0_0_32427792_27283.cpp:18:33: error: 'a' was not declared in this scope
   for(i=1;i<=n;i++) scanf("%d",&a[i].v);
                                 ^
0_0_32427792_27283.cpp:19:33: error: 'a' was not declared in this scope
   for(i=1;i<=n;i++) scanf("%d",&a[i].w);
                                 ^
0_0_32427792_27283.cpp:22:10: error: 'a' was not declared in this scope
     if(j-a[i].w>=0 && dp[i-1][j]<dp[i-1][j-a[i].w]+a[i].v)
          ^