Need Help writing a program...don't know where to start

[swtstrawberry]

All the basic stuff I get like cin/cout...but the interpolation formula, the for/while loop, and reading in the desired altitude...i dont get it....please help...anybody

here are the directions I got:

The program is supposed to determine the pressure, temperature, and density, by linear interpolation of atmospheric conditions given in a data table(a text file).
1. Read in the data table and store these table values in a 4 one dimensional arrays.
2.Declare a character variable, which takes on the value of c or q. 'c' is for continue and 'q' is for quit.
3.Print out (on screen) a request to enter the desired altitude.
4.Read in the desired altitude.
5.Use a for loop to establish the nearest altitude interval and the table properties to be used in the interpolation formula.
The interpolation formula is: y=y1+(z-z1)x(y2-y1)/(z2-z1)
where y represents any one of the variables of interest and z the altitude.
6.Print out to screen, the altitude z, and the interpolated values of pressure p, temperature t, and density rho, at specified altitudes. The output should identify which value goes with which variable. Also include the units of the variable.
7.Print out to screen the following statements 'do you wish to continue or quit'. On a new line print out 'enter c or q to continure or quit.
8.Enter 'c' or 'q'.
9 Use a while loop to cover a list of altitudes the user may wish to enter. You may need to initialize the character variable before the while loop.

[dariophoenix]

All the basic stuff I get like cin/cout...but the interpolation formula, the for/while loop, and reading in the desired altitude...i dont get it....please help...anybody

here are the directions I got:

The program is supposed to determine the pressure, temperature, and density, by linear interpolation of atmospheric conditions given in a data table(a text file).
1. Read in the data table and store these table values in a 4 one dimensional arrays.
2.Declare a character variable, which takes on the value of c or q. 'c' is for continue and 'q' is for quit.
3.Print out (on screen) a request to enter the desired altitude.
4.Read in the desired altitude.

cin can read directly any of the built-in types, so try something like (assuming the altitude is float; it should work for double, long double, etc)

float altitude;
cin >> altitude;

5.Use a for loop to establish the nearest altitude interval and the table properties to be used in the interpolation formula.
The interpolation formula is: y=y1+(z-z1)x(y2-y1)/(z2-z1)
where y represents any one of the variables of interest and z the altitude.

One way to do is putting the altitudes in a float vector and iterate through it like this:

vector <float> altitudesVector; // You'll need to #include <vector>
/* Read the file and load the values as float in the vector. The way to do it
* depends on the particular format of your input file. Once that is done... */

float smallestDifference = abs(altitude-altitudesVector[0]);
float nearestAltitude = altitudesVector[0];
for(int i = 1; i < altitudesVector.size() ; i++)
if ( abs(altitude-altitudesVector[i])<abs (altitude-nearestAltitude) )
nearestAltitude = altitudesVector[i];

6.Print out to screen, the altitude z, and the interpolated values of pressure p, temperature t, and density rho, at specified altitudes. The output should identify which value goes with which variable. Also include the units of the variable.
7.Print out to screen the following statements 'do you wish to continue or quit'. On a new line print out 'enter c or q to continure or quit.
8.Enter 'c' or 'q'.
9 Use a while loop to cover a list of altitudes the user may wish to enter. You may need to initialize the character variable before the while loop.

char goOn = 'Y';
while(goOn != 'N'){
cout << "Input an altitude: " << endl;
float altitude;
cin >> altitude;
cout << "Any more? Y/N " << endl;
cin >> goOn;
}

[swtstrawberry]

so, i'm trying to put 1 and 1 together but I still think its not even close to being correct...here is what I have :

# include<fstream.h>
# include<iostream.h>
# include<stdio.h>
# include<math.h>
# include<stdlib.h>
# include <vector>

double alt[101],temp[101],rho[101],press[101];
int i, ie;
char c, q;
main()
{
ifstream inf;
inf.open("atm7.txt",ios::in);
cout << "Enter Desired altitude: " << endl;
float altitude;
cin >> altitude;

char goOn = 'c';
while(goOn != 'q')

{
cout<<"Do you wish to continue or quit\n";
cout <<"Enter 'c' to continue or 'q' to quit\n" << endl;
cin >> goOn;
}

float smallestDifference = abs(altitude-altitudesVector[0]);
float nearestAltitude = altitudesVector[0];

for(int i = 0; i <=100,000 ; i+=1000)
if ( abs(altitude-altitudesVector[i])<abs (altitude-nearestAltitude) ) nearestAltitude = altitudesVector[i];

[D_C]

1. Read in the data table, store it, etc.

You say you figured out the cin, cout out, but what about the file I/O? I assume you have figured that out. Also, I assume that data is sorted by altitude, in ascending order.

9 Use a while loop to cover a list off altitudes the user may wish to enter. You may need to initialize the character variable before the while loop.

I'm not sure what this is asking for. I've done enough anyways, you can figure out the rest.

char input = '\0';
float altitude = 0.0f;
float temp = 0.0f;
float rho = 0.0f;
float press = 0.0f;
 
do
{
  cout << "Enter desired altitude: ";
  cin >> altitude;
 
  int i;
  for(i = 0; (i < altitude.length()-1) && (altitude[i] <= z); i++);
 
  if(i > 0)
    i--;
 
 
  temp = temp[i] +(altitude-altitude[i])*(temp[i+1]-temp[i])/(altitude[i+1]-altitude[i]);
 
  rho = // you do this one
  press = // and this one too
 
// I'm not sure what units you are using, you'll need to fix those
  cout << "Altitude:\t" << altitude << " altitude units (m ?)\n"
       << "Temperature:\t" << temp << " ºF/C\n"
       << "Temperature:\t" << rho << " density units (kg/m^3 ?)\n"
       << "Temperature:\t" << press << " pressure units (kPa ?)\n\n";
 
  do
  {
    cout << "Do you wish to continue or quit? ";
    cin >> input;
  } while(input != 'c' || input != 'q')
} while(input != 'q')

[swtstrawberry]

I wrote the program and the complier at school is Microsoft Visual 6.0.......but i keep getting one error message and i have no idea what it means...i bolded the line where it occurs n the error message i get....

# include<fstream.h>
# include<iostream.h>
# include<stdio.h>
# include<math.h>
# include<stdlib.h>





main()
{
double alt[105],temp[105],rho[105],press[105],desalt[105];
double z = 0.0f;
double p = 0.0f;
double t = 0.0f;
double r = 0.0f;
int i, ie;
char c, q, input;



ifstream inf;
inf.open("atm7.txt",ios::in);
i=1;

while (!inf.eof())
{
inf>>alt[i]>>temp[i]>>rho[i]>>press[i];
i++;
}
ie=i-1;


L1:;
printf("Enter Desired altitude: ");
error C2679: binary '>>' : no operator defined which takes a right-hand
operand of type 'double [105]' (or there is no acceptable conversion)
--------> cin>> desalt>>endl; printf("Desire altitude: ");
cout<<desalt<<endl;


for(i = 0; (i <=100000) && (alt[i]<= z); i+=1000);
{
t= temp[i] +(z-alt[i])*(temp[i+1]-temp[i])/(alt[i+1]-alt[i]);
r= rho[i] +(z-alt[i])*(rho[i+1]-rho[i])/(alt[i+1]-alt[i]);
p= press[i] +(z-alt[i])*(press[i+1]-press[i])/(alt[i+1]-alt[i]);

printf("Altitude (ft):\t");
cout<<alt <<endl;
printf("Pressure (lb per in^2):\t");
cout<< p <<endl;
printf("Temperature (F):\t");
cout<< t <<endl;
printf("Density (lb per ft^3):\t");
cout<< r <<endl;
}

do

{
printf("Do you wish to continue or quit?");
cin >> input;
}
while(input!='q'); goto L1;


return 0;

}

[Etaks]

Im kinda new to programming, and i REALLY dont know if im right (probably not) but i think the problem lies in this << or >>, try spaces in between as i saw a line where this happened (cout<<(text)<<endl;), dont flame me if im wrong