Error: passing 'const SunscreenSPF' as 'this' argument discards qualifiers issue

I am calculating how long one person can get sunburn with screen protection. As I like to use different approach to do things, I created a class called SunscreenSPF.

class SunscreenSPF  {  private:      string skinColor;      int SPF;      int time;    public:      SunscreenSPF(string skinColor, int SPF, int time)      {          this->skinColor=skinColor;          this->SPF=SPF;          this->time=time;      }        int calculateTime ()      {          return SPF*time;      }        friend ostream& operator<<(ostream &os, const SunscreenSPF &data)      {          os<<"Skin Color = "<<data.skinColor<<endl            <<"Time outdoors = "<<data.time<<endl            <<"SPF Level = "<<data.SPF<<endl            <<"Time to get sunburn with protection = "<<data.calculateTime()<<endl;      }  };  

I get this error: passing 'const SunscreenSPF' as 'this' argument discards qualifiers [-fpermissive]|

How can I fix this?

https://stackoverflow.com/questions/66757358/error-passing-const-sunscreenspf-as-this-argument-discards-qualifiers-issue March 23, 2021 at 12:40PM