/in/foo.cc: In function 'int main()':
/in/foo.cc:45:29: error: too few arguments to function 'std::__cxx11::string decode2(std::__cxx11::string&, int)'
  if (   (b == decode2(guess1) && c == decode3(guess1)
                             ^
/in/foo.cc:15:8: note: declared here
 string decode2(std::string& s, int k) {
        ^~~~~~~
/in/foo.cc:45:53: error: too few arguments to function 'std::__cxx11::string decode3(std::__cxx11::string&, int)'
  if (   (b == decode2(guess1) && c == decode3(guess1)
                                                     ^
/in/foo.cc:22:8: note: declared here
 string decode3(std::string& s, int k) {
        ^~~~~~~
/in/foo.cc:46:26: error: too few arguments to function 'std::__cxx11::string decode3(std::__cxx11::string&, int)'
   || (b == decode3(guess1) && c == decode2(guess1)
                          ^
/in/foo.cc:22:8: note: declared here
 string decode3(std::string& s, int k) {
        ^~~~~~~
/in/foo.cc:46:50: error: too few arguments to function 'std::__cxx11::string decode2(std::__cxx11::string&, int)'
   || (b == decode3(guess1) && c == decode2(guess1)
                                                  ^
/in/foo.cc:15:8: note: declared here
 string decode2(std::string& s, int k) {
        ^~~~~~~
/in/foo.cc:47:7: error: expected ')' before '{' token
     ) {
       ^
/in/foo.cc:50:2: error: expected ')' before 'else'
  else if (   (b == decode2(guess2) && c == decode3(guess2)
  ^~~~
/in/foo.cc:55:34: error: too few arguments to function 'std::__cxx11::string decode2(std::__cxx11::string&, int)'
  else if (   (b == decode2(guess3) && c == decode3(guess3)
                                  ^
/in/foo.cc:15:8: note: declared here
 string decode2(std::string& s, int k) {
        ^~~~~~~
/in/foo.cc:55:58: error: too few arguments to function 'std::__cxx11::string decode3(std::__cxx11::string&, int)'
  else if (   (b == decode2(guess3) && c == decode3(guess3)
                                                          ^
/in/foo.cc:22:8: note: declared here
 string decode3(std::string& s, int k) {
        ^~~~~~~
/in/foo.cc:56:26: error: too few arguments to function 'std::__cxx11::string decode3(std::__cxx11::string&, int)'
   || (b == decode3(guess3) && c == decode2(guess3)
                          ^
/in/foo.cc:22:8: note: declared here
 string decode3(std::string& s, int k) {
        ^~~~~~~
/in/foo.cc:56:50: error: too few arguments to function 'std::__cxx11::string decode2(std::__cxx11::string&, int)'
   || (b == decode3(guess3) && c == decode2(guess3)
                                                  ^
/in/foo.cc:15:8: note: declared here
 string decode2(std::string& s, int k) {
        ^~~~~~~
/in/foo.cc:58:4: error: expected ')' before 'std'
    std::cout << guess3;
    ^~~
/in/foo.cc:58:23: error: expected ')' before ';' token
    std::cout << guess3;
                       ^