Compilare: main.cpp: In function 'std::string getstring()': main.cpp:10:45: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 10 | while( 'a' <= a[ i ] && a[ i ] <= 'z' && i < a.size() ) { | ~~^~~~~~~~~~ main.cpp: In function 'int getno()': main.cpp:19:46: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 19 | while( '0' <= a[ i ] && a[ i ] <= '9' && i < a.size() ) { | ~~^~~~~~~~~~ main.cpp: In function 'std::string exp()': main.cpp:28:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 28 | if( i >= a.size() ) | ~~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:76:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare] 76 | for( int i = 0; i < a.size(); i++ ) | ~~^~~~~~~~~~