friends.cpp: In function 'int main()':
friends.cpp:19:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
19 | for (int i=0; i<s.size()/2; ++i) {
| ~^~~~~~~~~~~
friends.cpp:25:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
25 | for (int i=0; i<=s.size()/2; ++i) {
| ~^~~~~~~~~~~~
friends.cpp:26:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
26 | if (s[i]!=s[i+s.size()/2+1] || i==s.size()/2) {
| ~^~~~~~~~~~~~
friends.cpp:46:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
46 | for (int i=s.size()/2; i<s.size(); ++i) {
| ~^~~~~~~~~
friends.cpp:47:39: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
47 | if (s[i]!=s[i-s.size()/2] || i==s.size()-1) {
| ~^~~~~~~~~~~~
friends.cpp:52:29: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
52 | for (int i=s.size()-1; i>=s.size()/2; --i) {
| ~^~~~~~~~~~~~
friends.cpp:53:41: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
53 | if (s[i]!=s[i-s.size()/2-1] || i==s.size()/2) {
| ~^~~~~~~~~~~~
friends.cpp:70:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
70 | while (k<s.size()/2) {
| ~^~~~~~~~~~~