Compilare: main.cpp: In function 'void insert(TrieNode*, std::string)': main.cpp:30:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 30 | for (int i = 0; i < key.length(); i++) | ~~^~~~~~~~~~~~~~ main.cpp: In function 'int getNumberOfApparitions(TrieNode*, std::string)': main.cpp:45:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 45 | for (int i = 0; i < key.length(); i++) | ~~^~~~~~~~~~~~~~ main.cpp: In function 'void deleteNode(TrieNode*, std::string)': main.cpp:67:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 67 | for (int i = 0; i < key.length(); i++) | ~~^~~~~~~~~~~~~~ main.cpp: In function 'int getLongestPrefix(TrieNode*, std::string)': main.cpp:85:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 85 | for(i = 0; i < key.length(); i++) | ~~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:98:20: warning: unused variable 'i' [-Wunused-variable] 98 | int operation, i, longestSubstringLength; | ^ main.cpp:98:23: warning: unused variable 'longestSubstringLength' [-Wunused-variable] 98 | int operation, i, longestSubstringLength; | ^~~~~~~~~~~~~~~~~~~~~~