/in/foo.cc: In function 'int main()':
/in/foo.cc:16:15: error: lvalue required as left operand of assignment
   else if(n%2=0) {mid2=n/2;for(i=1;i<mid2;i++) {x=up[n-i+1];up[n-i+1]=up[i];up[i]=x} }
               ^
/in/foo.cc:16:84: error: expected ';' before '}' token
   else if(n%2=0) {mid2=n/2;for(i=1;i<mid2;i++) {x=up[n-i+1];up[n-i+1]=up[i];up[i]=x} }
                                                                                    ^