View Compilation Error

0_0_14143364_25810.cpp: In function 'bool read(int&)':
0_0_14143364_25810.cpp:5:9: error: 'ch' was not declared in this scope
  for (++ch; (*ch) && !(((*ch) >= '0' && (*ch) <= '9') || (*ch) == '-' ); ++ch);
         ^
0_0_14143364_25810.cpp:6:8: error: 'ch' was not declared in this scope
  if(!(*ch)) return false;
        ^
0_0_14143364_25810.cpp:8:7: error: 'ch' was not declared in this scope
  if((*ch) == '-') { sign = 1; ++ch; }
       ^
0_0_14143364_25810.cpp:9:22: error: 'ch' was not declared in this scope
  for (x = 0; '0' <= *ch; ch++) x = x * 10 + *ch - '0';
                      ^