View Compilation Error

0_0_33377965_28146.cpp:49:9: error: expected unqualified-id before 'else'
         else if(op[0]=='A')update(a,b,1,n,1);
         ^
0_0_33377965_28146.cpp:50:10: error: expected unqualified-id before 'else'
          else update(a,-b,1,n,1);
          ^
0_0_33377965_28146.cpp:51:1: error: expected unqualified-id before '{' token
 {
 ^