View Compilation Error

0_0_25291886_30683.cpp:22:28: error: 'a' does not name a type
 const double pi=acos(-1.0);a
                            ^
0_0_25291886_30683.cpp: In function 'void init()':
0_0_25291886_30683.cpp:29:20: error: 'ans' was not declared in this scope
         if(i%4==0) ans[i]=(i*i)/8;
                    ^
0_0_25291886_30683.cpp:30:20: error: 'ans' was not declared in this scope
         if(i%4==1) ans[i]=ans[i-1]+i/4-0.5;
                    ^
0_0_25291886_30683.cpp:31:20: error: 'ans' was not declared in this scope
         if(i%4==2) ans[i]=(i/4)*(i/4+1)*2;
                    ^
0_0_25291886_30683.cpp:32:20: error: 'ans' was not declared in this scope
         if(i%4==3) ans[i]=ans[i-1]+i/4+0.5;
                    ^
0_0_25291886_30683.cpp: In function 'int main()':
0_0_25291886_30683.cpp:46:16: error: 'ans' was not declared in this scope
             if(ans[i]>=num){
                ^