help please -Choose limit of an array

[facebookisgayyy]

I'd like the user to be able to input a range for the array, I've made it able to be set to a high, but I don't know how to set the low
i.e:
right now you can set 20 and it'll print 1-20
but I want it to print (for example) 7-20, or 13-20, etc etc

//Brandon Thomas
# include<iostream>
using namespace std;
int main( )
{
 srand(time(0));
 int counter = 0;
 int a;
 
  cout << "Please enter length of array (zero through x)" << endl;
  cin  >> a;
  a++;
  system("CLS");
  int y[a];
  
  for(int loop = 0; loop <= a; loop++){
   y[counter] = counter;
   counter++;
  }
 
 int z = sizeof(y)/sizeof(y[0]);
 
 random_shuffle(y, y+z);
      
  for(int x = 0; x < z; x++){         
   cout << y[x] << endl;     
  } 
 
 system("PAUSE");
} 

[jaded7]

Try using the modulo operator. This gives the remainder, after being divided by it. For example:

20%10 means that if you divide 20 by 10, you have a remainder of 0, so it evaluates to 0.

7%5 means that if you divide 7 by 5, you have a remainder of 2, so it evaluates to 2.

I'll let you figure out how that is implemented. Good luck!

[facebookisgayyy]

@jaded7

i really don't understand how that is implemented, this is for my programming class in HS and i'm *very* new to dealing with arrays

[facebookisgayyy]

If I test this using for example: a low of 10 and a high of 20, it will print 10-20, but for numbers like 1-9 it prints garbage out of memory.

//Brandon Thomas
# include<iostream>
using namespace std;
int main()
{ 
  srand(time(0));
  //H/L Variables
  int a, b;
  //Instructions
  cout << "Please enter high and low of array" << endl;
  //Sets Length of the Array (ie. A = 20, 0-20 is generated)
  cin  >> a;
  //Sets lowest number to appear on screen
  cin  >> b;
  //Sets the rising counter to the lowest number
  int counter = b;
  
  system("CLS");
  //Sets the Array to A (Length)
  int y[a];
  
  //Loads Numbers into Array
  for(int loop = 0; loop <= a-b; loop++)
  {
   //Loop is position in Array, so starts at 0
   //Counter is equivalent to the Low, so I'll use 4 as example
   y[loop] = counter;
   counter++;
  }
  
  //Shuffles numbers within the Array
  int z = sizeof(y)/sizeof(y[0]);
  random_shuffle(y, y+z);
  
  //Prints shuffled numbers
  for(int x = 0; x < z; x++)
  {         
   cout << y[x] << endl;     
  } 
  
  system("PAUSE");
} 

[jaded7]

Sorry, I'll explain a bit more.

If you have, say, N%10 where n is any number, it means that you can have the values 0 through 9. That is because you would have 0 as a remainder, after you divide n by 10, or you can have up to 9 as a remainder. For example, 13%10 gives you 3, 19%10 returns 9, 20%10 returns 0, etc.


In general, if you have the expression: a+N%b, where a, b are constants and N is a variable integer, then you have a minimum value of (b-a) and a maximum value of (a+b)-1.

example: 6+N%12
a = 6, b = 12
min: 6
max: 17


Double check this- its late where I live and im quite tired


Edit: I think i may have misunderstood what you're trying to do. Can you explain exactly what it is youre doing?

[facebookisgayyy]

@jaded7

-Generate Numbers based off user input
-Have them outputted in a random order
-User Input selects range of the numbers to be output: (Low and High)
-No 2 numbers can be repeated

Try running the program I have right above your most recent post, first try the Input
20 (enter) 1

it prints the numbers 1-20 in a random order without any repeats

then try the input
20 (enter) 10

It's doesnt print 1-9 (as it's told) but instead of printing 1,2,3,4,5,6,7,8 and 9, it prints garbage in place of those integers