I can't get the loops right. It does it a different way every time & i need to add a third loop if they input invalid miles.

[poobear]

#include <iostream>
using namespace std;


double computeVehicleCost(double overageRate, int freeMiles, double dailyFee, int estimatedMiles);
int main()
{


const double CLASS_E_DAILY_FEE = 45.90;
const int CLASS_E_FREE_MILES = 40;
const double CLASS_E_OVERAGE_RATE = 0.25;
const double CLASS_S_DAILY_FEE = 57.75;
const int CLASS_S_FREE_MILES = 120;
const double CLASS_S_OVERAGE_RATE = 0.40;
const double CLASS_L_DAILY_FEE = 85.50;
const int CLASS_L_FREE_MILES = 200;
const double CLASS_L_OVERAGE_RATE = 0.50;
const double CLASS_V_DAILY_FEE = 55.00;
const int CLASS_V_FREE_MILES = 150;
const double CLASS_V_OVERAGE_RATE = 0.50;
const double CLASS_T_DAILY_FEE = 55.00;
const int CLASS_T_FREE_MILES = 150;
const double CLASS_T_OVERAGE_RATE = 0.50;


int estimatedMiles, a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z;
char classOfVehicle, anotherQuote;
double selectedVehicleCost, eCost, sCost, lCost, vCost, tCost;
bool run=true;
bool go=true;

while(run)
{


cout << "Enter the class of the vehicle. E for economy, S for Sport, L for luxury, V for van, or T for truck: ";
cin >> classOfVehicle;



if (classOfVehicle == a,b,c,d,f,g,h,i,j,k,m,n,o,p,q,r,u,w,x,y,z || classOfVehicle == A,B,C,D,F,G,H,I,J,K,M,N,O,P,Q,R,U,W,X,Y,Z)
{
go=false;


cout << "Invalid input please enter E for economy, S for Sport, L for luxury, V for van, or T for truck: ";
cin >> classOfVehicle; }

else; {go=true;
}



cout << "Please enter the estimated miles (1 to 812): ";
cin >> estimatedMiles;

eCost = computeVehicleCost(CLASS_E_OVERAGE_RATE, CLASS_E_FREE_MILES, CLASS_E_DAILY_FEE, estimatedMiles);
lCost = computeVehicleCost(CLASS_L_OVERAGE_RATE, CLASS_L_FREE_MILES, CLASS_L_DAILY_FEE, estimatedMiles);
sCost = computeVehicleCost(CLASS_S_OVERAGE_RATE, CLASS_S_FREE_MILES, CLASS_S_DAILY_FEE, estimatedMiles);
vCost = computeVehicleCost(CLASS_V_OVERAGE_RATE, CLASS_V_FREE_MILES, CLASS_V_DAILY_FEE, estimatedMiles);
tCost = computeVehicleCost(CLASS_T_OVERAGE_RATE, CLASS_T_FREE_MILES, CLASS_T_DAILY_FEE, estimatedMiles);

cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2);


switch (classOfVehicle)
{
case 'E':
case 'e':
cout << "Economy vehicle cost: $" << eCost << endl;
selectedVehicleCost = eCost;
break;
case 'S':
case 's':
cout << "Sport vehicle cost: $" << sCost << endl;
selectedVehicleCost = sCost;
break;
case 'L':
case 'l':
cout << "Luxury vehicle cost: $" << lCost << endl;
selectedVehicleCost = lCost;
break;
case 'V':
case 'v':
cout << "Van vehicle cost: $" << vCost << endl;
selectedVehicleCost = vCost;
break;
case 'T':
case 't':
cout << "Truck vehicle cost: $" << tCost << endl;
selectedVehicleCost = tCost;
break;
}

if (eCost < selectedVehicleCost)
{
cout << "Economy is cheaper by: $" << selectedVehicleCost - eCost << endl;
}
if (sCost < selectedVehicleCost)
{
cout << "Sport is cheaper by: $" << selectedVehicleCost - sCost << endl;
}
if (lCost < selectedVehicleCost)
{
cout << "Luxury is cheaper by: $" << selectedVehicleCost - lCost << endl;
}
if (vCost < selectedVehicleCost)
{
cout << "Van is cheaper by: $" << selectedVehicleCost - vCost << endl;
}
if (tCost < selectedVehicleCost)
{
cout << "Truck is cheaper by: $" << selectedVehicleCost - tCost << endl;
}


cout << "Would you like another quote. Press Y for yes and N for no: ";
cin >> anotherQuote;

if(anotherQuote =='N'||anotherQuote =='n'){
run = false;}
else (anotherQuote == a,b,c,d,e,f,g,h,i,j,k,l,m,o,p,q,r,s,t,u,v,w,x,z || anotherQuote == A,B,C,D,E,F,G,H,I,J,K,L,M,O,P,Q,R,S,T,U,V,W,Z);
{
run = false;
cout << "Invalid input. Would you like another quote. Press Y for yes N for no: ";
cin >> anotherQuote;
}
if(anotherQuote =='N'||anotherQuote =='n'){
run = false;}

}
return 0;
}



double computeVehicleCost(double overageRate, int freeMiles, double dailyFee, int estimatedMiles)

{
double vehicleCost = dailyFee;

if (estimatedMiles > freeMiles)
{
vehicleCost += (estimatedMiles - freeMiles) * overageRate;
}
return vehicleCost;
}

[jonnin]

help us help you.
explain exactly what you need.
use code tags.

you have a jillion integers with no initial value that you are making a mess with.
the letter a when typed by a user is 'a'.
int a; //a random value
if(x == a)//meaningless, a is random.

you want something like
if x is between a-z or A-Z which looks like this:
if( x >='a' && x <= 'z') || (x >='A' && x<='Z'))
I think. Its a bit hard to mind read what you want, but taking a guess.
there is a built in test if something is an ascii letter.
the above is the same as if(isalpha(x))
double quotes are strings, single quotes are letters, when coding literal values.