View Compilation Error

0_0_22134552_5532.cpp:15:10: error: 'N' was not declared in this scope
 double d[N];
          ^
0_0_22134552_5532.cpp: In function 'int main()':
0_0_22134552_5532.cpp:20:14: error: 'd' was not declared in this scope
   if(i%4==0) d[i]=(i*i)/8;
              ^
0_0_22134552_5532.cpp:21:14: error: 'd' was not declared in this scope
   if(i%4==1) d[i]=d[i-1]+i/4-0.5;
              ^
0_0_22134552_5532.cpp:22:14: error: 'd' was not declared in this scope
   if(i%4==2) d[i]=(i/4)*(i/4+1)*2;
              ^
0_0_22134552_5532.cpp:23:14: error: 'd' was not declared in this scope
   if(i%4==3) d[i]=d[i-1]+i/4+0.5;
              ^
0_0_22134552_5532.cpp:33:7: error: 'd' was not declared in this scope
    if(d[i]>=n)
       ^