implementer.cpp: In function ‘char nextch()’:
implementer.cpp:15:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   15 |     if (pos == BUF_SIZE) fread(buf, BUF_SIZE, 1, fin), pos = 0;
      |                          ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
answer.code: In function ‘int add(int, int)’:
answer.code:15:25: error: ‘｛return’ was not declared in this scope
   15 |         if(a + b < MOD) ｛return a + b;｝
      |                         ^~~~~~~~
answer.code:15:40: error: ‘｝’ was not declared in this scope
   15 |         if(a + b < MOD) ｛return a + b;｝
      |                                        ^~
answer.code:17:1: warning: no return statement in function returning non-void [-Wreturn-type]
   17 | }
      | ^