I think you should tell us what is should be outputting that it isn't. I compiled and run it and it works "just fine", ignoring the warnings:
Code:
In function ‘int main()’:
25:9: warning: unused variable ‘vechileExpense’ [-Wunused-variable]
double vechileExpense;
^~~~~~~~~~~~~~
32:9: warning: variable ‘mealTotal’ set but not used [-Wunused-but-set-variable]
double mealTotal;
^~~~~~~~~
33:9: warning: unused variable ‘total’ [-Wunused-variable]
double total;
^~~~~
37:9: warning: unused variable ‘nightlyRate’ [-Wunused-variable]
double nightlyRate;
^~~~~~~~~~~
49:6: warning: variable ‘d’ set but not used [-Wunused-but-set-variable]
int d;
^
50:9: warning: unused variable ‘parkingSpent’ [-Wunused-variable]
double parkingSpent;
^~~~~~~~~~~~
51:9: warning: variable ‘taxiSpent’ set but not used [-Wunused-but-set-variable]
double taxiSpent;
^~~~~~~~~
In function ‘void getParkingAmount(double&, double&)’:
244:6: warning: unused variable ‘days’ [-Wunused-variable]
int days;
^~~~
242:51: warning: unused parameter ‘allowedParking’ [-Wunused-parameter]
void getParkingAmount(double &parkingFee, double &allowedParking){
^~~~~~~~~~~~~~
In function ‘void getTaxiAmount(double&, double&)’:
259:6: warning: unused variable ‘days’ [-Wunused-variable]
int days;
^~~~
257:46: warning: unused parameter ‘allowedTaxiFee’ [-Wunused-parameter]
void getTaxiAmount (double &taxiFee, double &allowedTaxiFee){
^~~~~~~~~~~~~~
In function ‘void getHotelAmount(double&, double&)’:
289:9: warning: variable ‘hotelFeeTotal’ set but not used [-Wunused-but-set-variable]
double hotelFeeTotal;
^~~~~~~~~~~~~
290:6: warning: unused variable ‘days’ [-Wunused-variable]
int days;
^~~~
287:46: warning: unused parameter ‘allowedHotelFee’ [-Wunused-parameter]
void getHotelAmount(double &hotelFee,double &allowedHotelFee){
^~~~~~~~~~~~~~~
In function ‘void getMealAmount(double&, double&)’:
309:6: warning: unused variable ‘day’ [-Wunused-variable]
int day;
^~~
314:9: warning: unused variable ‘firstDay’ [-Wunused-variable]
double firstDay;
^~~~~~~~
315:9: warning: unused variable ‘lastDay’ [-Wunused-variable]
double lastDay;
^~~~~~~
307:28: warning: unused parameter ‘allowedMealTotal’ [-Wunused-parameter]
void getMealAmount(double &allowedMealTotal, double &spentMealTotal){
^~~~~~~~~~~~~~~~
307:54: warning: unused parameter ‘spentMealTotal’ [-Wunused-parameter]
void getMealAmount(double &allowedMealTotal, double &spentMealTotal){
^~~~~~~~~~~~~~
In function ‘int main()’:
72:13: warning: ‘airfareFee’ may be used uninitialized in this function [-Wmaybe-uninitialized]
airfareFee = getAirfareAmount (airfareFee);
~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
74:15: warning: ‘carRentalFee’ may be used uninitialized in this function [-Wmaybe-uninitialized]
carRentalFee = getCarRentalAmount (carRentalFee);
~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
76:27: warning: ‘privateCarFee’ may be used uninitialized in this function [-Wmaybe-uninitialized]
getPrivateVechileExpense (privateCarFee);
~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~
92:18: warning: ‘registrationFee’ may be used uninitialized in this function [-Wmaybe-uninitialized]
registrationFee = getRegistrationFee (registrationFee);
~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
110:28: warning: ‘breaksfastFee’ may be used uninitialized in this function [-Wmaybe-uninitialized]
mealTotal = breaksfastFee + lunchFee + dinnerFee;
~~~~~~~~~~~~~~^~~~~~~~~~
110:28: warning: ‘lunchFee’ may be used uninitialized in this function [-Wmaybe-uninitialized]
110:12: warning: ‘dinnerFee’ may be used uninitialized in this function [-Wmaybe-uninitialized]
mealTotal = breaksfastFee + lunchFee + dinnerFee;
~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
145:33: warning: ‘hotelFeeTotal’ may be used uninitialized in this function [-Wmaybe-uninitialized]
cout << "Hotel" << setw(22) << hotelFeeTotal << setw(20) << allowedHotelFee << endl;
^~~~~~~~~~~~~