Borderou de evaluare (job #670543)

Compilare: main.cpp: In function 'int read()': main.cpp:21:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'unsigned int'} [-Wsign-compare] 21 | while( i < s.size() && isdigit( s[i] ) ) { | ~~^~~~~~~~~~ main.cpp:25:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'unsigned int'} [-Wsign-compare] 25 | while( i < s.size() && !isalnum( s[i] ) ) | ~~^~~~~~~~~~ main.cpp:28:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'unsigned int'} [-Wsign-compare] 28 | while( i < s.size() && isalpha( s[i] ) ) | ~~^~~~~~~~~~ main.cpp:30:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'unsigned int'} [-Wsign-compare] 30 | while( i < s.size() && !isalnum( s[i] ) ) | ~~^~~~~~~~~~