H1 Solutions

Tests

Comments

Lex/yacc comments:

• "sqrt(" is two tokens 'sqrt' and '('.
• Use [ \t]+ ; to strip white spaces. Some students had problems in their scanner because they failed to strip out white spaces properly.
• Precedence and associativity section caused many problems. Check solution for an acceptable way to handle these.
• Many students failed to check if a variable is defined.

C++/STL comments:

• Using map<char*,double> is probably not what is needed. It uses address as the key, which makes no sense unless you are writing a cache simulator or something like that. The proper way is map<string,double>.
• Having map<string,double> for variable values and map<string,bool> to keep track which variable is defined is a poor programming practice. Use map::find() to check if a variable is already defined. map::operator[]() inserts its arguments into the map and pollutes your symbol table.