lab5.h:94:30: error: empty character constant while(full_name [i]!= '')

Need help with this error in C++

this is my code and error in the end :

Extracted text: lab5.h:94:30: error: empty character constant while(full_name [i]!= '')


Extracted text: std::string extractLastName (std::string full_name, std::string email){ int i = 0; while(i='A' && c1<='z') c1="" +="32;" if(c2="">='A' && c2<='z') c1="" +="32;" if(c1!="c2)" break;="" j++;="" k++;="" }="" if(j="=" full.name.length())="" return="" full_name.substr(i);="" }="" return="" "";="">