  double Distance::inputfeet0(double feet0) { if(feet0 < 0) {     cout<<"Cannot be less than zero. Default value of 0 is used."; } else {     feet_0 = feet0; }  double Distance::inputinch0(double inch0) { if(inch0 < 0) {     cout<<"Cannot be less than zero. Default value of 0 is being used."; } else {     inch_0 = inch0; }  }  double Distance::inputinch0(double inch0) { if(inch0 < 0) {     cout<<"Cannot be less than zero. Default value of 0 is being used."; } else {     inch_0 = inch0; } 