View Compilation Error

0_0_39413569_23035.cpp: In function 'void test()':
0_0_39413569_23035.cpp:50:13: error: no matching function for call to 'KMP::fnex()'
   50 |     kmp.fnex();
      |     ~~~~~~~~^~
0_0_39413569_23035.cpp:21:17: note: candidate: 'static void KMP::fnex(std::string&)'
   21 |     static void fnex(string &s){
      |                 ^~~~
0_0_39413569_23035.cpp:21:17: note:   candidate expects 1 argument, 0 provided