View Compilation Error

0_0_33238765_18916.cpp: In function 'void solve()':
0_0_33238765_18916.cpp:22:16: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
  for(int i=0;i<q;i++){
                ^
0_0_33238765_18916.cpp:23:14: error: 'a' was not declared in this scope
   scanf("%s",a);
              ^