palindrome.cpp: In function 'bool is_palindrome(std::string)':
palindrome.cpp:8:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
8 | for (int i = 0; i < a.size(); ++i) {
| ~~^~~~~~~~~~
palindrome.cpp: In function 'int main()':
palindrome.cpp:18:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
18 | for (int i = 1; i <= a.size(); ++i) {
| ~~^~~~~~~~~~~
palindrome.cpp:19:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'long long unsigned int' [-Wsign-compare]
19 | for (int j = 0; j <= a.size() - i; ++j) {
| ~~^~~~~~~~~~~~~~~
palindrome.cpp:24:23: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
24 | for (int i = 1; i <= a.size(); ++i) {
| ~~^~~~~~~~~~~
palindrome.cpp:25:27: warning: comparison of integer expressions of different signedness: 'long long int' and 'long long unsigned int' [-Wsign-compare]
25 | for (int j = 0; j <= a.size() - i; ++j) {
| ~~^~~~~~~~~~~~~~~