View Compilation Error

0_0_27685821_16210.cpp: In function 'int cmp(const void*, const void*)':
0_0_27685821_16210.cpp:15:2: error: 'person' was not declared in this scope
  person *a=(per*)q,*b=(per*)w;
  ^
0_0_27685821_16210.cpp:15:10: error: 'a' was not declared in this scope
  person *a=(per*)q,*b=(per*)w;
          ^
0_0_27685821_16210.cpp:15:21: error: 'b' was not declared in this scope
  person *a=(per*)q,*b=(per*)w;
                     ^
0_0_27685821_16210.cpp: In function 'int to_int(char*)':
0_0_27685821_16210.cpp:24:10: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
   if(*p=="-"||*p=='0')
          ^
0_0_27685821_16210.cpp: In function 'int main()':
0_0_27685821_16210.cpp:64:33: error: 'qosort' was not declared in this scope
  qosort(acm,i,sizeof(acm[0]),cmp);
                                 ^