For loop to determine a range?

[Omeyer]

Guys,

I thought I had a solution figured out for an assignment, but finally after getting word back from my instructor, it is incorrect.

Basically, I am having trouble figuring out how to isolate a range of numbers from a list, and display values associated with those numbers. For example, if the list of numbers is:

0 = terminate program
10 = value1
20 = value2
30 = value3
40 = value4
50 = value5
60 = value6
70 = value7
80 = value8
90 = value9
100 = value10

And I prompt the user to enter two numbers, (start and end) how can I display, for example, all the values from 40 to 70?

void displayRange (int, int);

int main()
{

int start, end;

do 
{
	cout << "Enter a number range" << endl;
	cin >> start >> end; //User enters two numbers which defines the range

	if (start != 0)
	{
	cout << "The range of values include:" << endl;
    for (start = 1; start < end; value++) //Not sure how to work this For loop to determine the range entered by the user
		displayRange(start, end);  //Function to display values in range
	}
	
}while (start != 0); //0 Terminates Loop

		cin.get();
		cin.get();
		return 0;
}

displayRange (int start, int end)
{
	if (start >= 10)
		cout << "value1";
	if (start >= 20)
		cout << "value2";
	if (start >= 30)
		cout << "value3";
	if (start >= 40)
		cout << "value4";
	if (start >= 50)
		cout << "value5";
	 	.
		.
		.

	

[pogrady]

Is this list in a file?

[Omeyer]

No, not from a file

[greenleaf800073]

Here is something of the sort

#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;

int main(int nNumberofArgs, char* pszArgs[])
{
    cout << "Here is a program to make a number line" << endl;
    int value1 = 0;
    int value2 = 0;


        cout << "Enter two numbers: " << endl;
        cin >> value1 >> value2;

        if (value1 < -50000 || value2 > 50000)
        {
            cout << "Please enter two numbers between -50000 and 50000" << endl;
            return 0;
        }

   if (value1 < value2)
{
    cout << "Here are the numbers between " << value1 << " and " << value2 << endl;
    cout << value1 << endl;
    while (value1 < value2)
    {
            value1++;
            cout << value1 << " \n";
    }
}
    if (value1 > value2)
    {
        cout << "Here are the numbers between " << value2 << " and " << value1 << endl;
        cout << value2 << endl;
        while (value2 < value1)
        {
                value2++;
                cout << value2 << " \n";
        }
    }

    system("PAUSE");
    return 0;
}

[pogrady]

You'll want to use an array of integers:

int ValueArray[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 0};

then you'll need to use your displayrange function:

displayRange (int start, int end)
{
	if (start >= 10)
		cout << ValueArray[0];
	if (start >= 20)
		cout <<  ValueArray[1];
	if (start >= 30)
		cout <<  ValueArray[2];
	if (start >= 40)
		cout <<  ValueArray[3];
	if (start >= 50)
		cout <<  ValueArray[4];

Kinda make sense?

[Omeyer]

Arrays will be in the next chapter- havent covered them yet. I will read up on it though. Yes, that seems to make sense, but I am a little confused because I need to print out a string, not a number.

[Yanson]

Like this maybe?

#include <iostream>
using namespace std;

void displayRange (int, int);

int main()
{

	int start, end;

	do 
	{
		cout << "Enter a number range" << endl;
		cin >> start >> end; //User enters two numbers which defines the range
		cin.ignore();

		if (start != 0)
		{
			cout << "The range of values include:" << endl;
			displayRange(start, end);  //Function to display values in range
		}
	
	}while (start != 0); //0 Terminates Loop

		
	cin.ignore();
	return 0;
}

void displayRange (int start, int end)
{
	if (start <= 10 && end >= 10)
		cout << "value1" << endl;
	if (start <= 20 && end >= 20)
		cout << "value2" << endl;
	if (start <= 30 && end >= 30)
		cout << "value3" << endl;
	if (start <= 40 && end >= 40)
		cout << "value4" << endl;
	if (start <= 50 && end >= 50)
		cout << "value5" << endl;
}

[pogrady]

If you have to do it without arrays:

for(unsigned int x = Start; x <= End; x += 10)
{
   switch(x)
    {  
       case 10:
            std::cout<<"Value 1"<<std::endl;
            break;
       case 20:
            std::cout<<"Value 2"<<std::endl;
            break;
       case 30:
            std::cout<<"Value 3"<<std::endl;
            break;
       case 40:
            std::cout<<"Value 4"<<std::endl;
            break;
       case 50:
            std::cout<<"Value 5"<<std::endl;
            break;
       case 60:
            std::cout<<"Value 6"<<std::endl;
            break;
       case 70:
            std::cout<<"Value 7"<<std::endl;
            break;
       case 80:
            std::cout<<"Value 8"<<std::endl;
            break;
       case 90:
            std::cout<<"Value 9"<<std::endl;
            break;
       case 100:
            std::cout<<"Value 10"<<std::endl;
            break;
    }
}

this loops though x as a multiple of 10 and executes each switch statement. Notice that x can be incremented by something other then one.

[Omeyer]

@ Yanson: Thats what I had originally, but if a user enters something like 22 and 85, then I need to display all of the values in that range.

@pogrady: That looks good, but I am trying to translate it to my actual problem- I might have given a bad example

[Omeyer]

removed

[Omeyer]

removed

[JLBorges]

Use a lookup table, perhaps?

Something like this:

#include <iostream>

void print_period_names( int start, int end )
{
    constexpr int N = 12 ;
    static const char* const period_name[N] =
    {
        "Neogene", "Paleogene", "Cretaceous", "Jurassic", "Triassic", "Permian",
        "Carboniferous", "Devonian", "Silurian", "Ordovician", "Cambrian", "Precambrian"
    };

    static const int period_max[N] =
    {
       65, 135, 192, 225, 280, 345, 395, 435, 500, 570, 4500, 99999999
    };

    if( start<999999 && end>start )
    {
        int s = 0 ;
        while( start > period_max[s] ) ++s ;

        int f = N-1 ;
        while( end < period_max[f] ) --f ;

        for( int i = s ; i <= f ; ++i ) std::cout << period_name[i] << '\n' ;
    }
}

int main()
{
   print_period_names( 395, 4500 ) ;
}