Compilare: main.cpp: In function 'int main()': main.cpp:67:33: 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 k = 0; k<c.size(); k++) | ~^~~~~~~~~ main.cpp:134:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 134 | for(int dif = 1; dif<c.size(); dif++) | ~~~^~~~~~~~~ main.cpp:136:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 136 | for(int a = 1; a+dif<=c.size(); a++) | ~~~~~^~~~~~~~~~