Please help program to find distance btwn cities using array of structs

[radskate360]

Hi I am newer to programming and need a bit of help with this program.



OK, heres the directions.



The distance between two places on earth can be calculated by using their latitudes and longitudes. The calculation for this is as follows: (The latitudes and longitudes must be converted to radians (radians=degrees * pi / 180)). PI must be set set to 20 decimals as follows: PI = 3.1419265358979323846 Earth's Radius = 3963.1

Definitions: acos is arccosine; sin is sine; cos is cosine.

Calculation formula:



miles = acos(cos(lat1)*cos(long1)*cos(lat2)*cos(long2)+cos (lat1)*sin(long1)*cos(lat2)*sin(long2)+sin(lat1)*s in(lat2))*earth radius



The chart shows the latitude and longitude in degrees of 20 various locations around the world. These should be read in from a file, named latlong.txt and for each location hold its name, latitude and longitude.



Write a Program using an array of structs, that will allow the user to choose location 1 and location 2 from a menu and calculate the approximate distance between them.



So here is what the file should look like



Ankara Turkey 40.03000 32.90000
Aukland New Zealand -36.88320 174.75000
Buenos Aires Argentina -34.33320 -58.49990
Calcutta India 22.53330 88.36670
Copenhagen Denmark 55.71670 12.45000



There is a total of 20 locations but here are the first few. When displayed in the menu in the beginning they need to be listed with numbers next to them. So it will output enter starting destination and you type in the number of the starting location and then the number of the ending location. and it will compute the distance using the formula.



I am not familiar with the array of structs so any help would be great



I think the file can contain the city and its coordinates as listed about of can be listed like this:



Ankara Turkey
40.03000
32.90000



I really appreciate all the help..

[ilikepython]

Hi I am newer to programming and need a bit of help with this program.



OK, heres the directions.



The distance between two places on earth can be calculated by using their latitudes and longitudes. The calculation for this is as follows: (The latitudes and longitudes must be converted to radians (radians=degrees * pi / 180)). PI must be set set to 20 decimals as follows: PI = 3.1419265358979323846 Earth's Radius = 3963.1

Definitions: acos is arccosine; sin is sine; cos is cosine.

Calculation formula:



miles = acos(cos(lat1)*cos(long1)*cos(lat2)*cos(long2)+cos (lat1)*sin(long1)*cos(lat2)*sin(long2)+sin(lat1)*s in(lat2))*earth radius



The chart shows the latitude and longitude in degrees of 20 various locations around the world. These should be read in from a file, named latlong.txt and for each location hold its name, latitude and longitude.



Write a Program using an array of structs, that will allow the user to choose location 1 and location 2 from a menu and calculate the approximate distance between them.



So here is what the file should look like



Ankara Turkey 40.03000 32.90000
Aukland New Zealand -36.88320 174.75000
Buenos Aires Argentina -34.33320 -58.49990
Calcutta India 22.53330 88.36670
Copenhagen Denmark 55.71670 12.45000



There is a total of 20 locations but here are the first few. When displayed in the menu in the beginning they need to be listed with numbers next to them. So it will output enter starting destination and you type in the number of the starting location and then the number of the ending location. and it will compute the distance using the formula.



I am not familiar with the array of structs so any help would be great



I think the file can contain the city and its coordinates as listed about of can be listed like this:



Ankara Turkey
40.03000
32.90000



I really appreciate all the help..

So by array of structs I think they means something like this:

struct City
{
    char cityname[30]; // "Ankara"
    char country[30]; // "Turkey"
    double latitude; // 40.03
    double longitude; // 32.9
};
 

Then you would, read the information in from a file, and store it in an array of structs "City":

City cities[20];   // declare array of 20 "cities"
 
open file
read file with loop
    store results in cities[x]
    increment x   // or whatever your variable will be
 

Now that you have your information, you just need to make the loop of the program where you will ge the two locations, and calculate the distance. Do you have any problems with that?