Divide array

[peter hurley]

I have a stream of numbers that I want to divide into two separate arrays
my coding works while in the loop but not if I try to output the two arrays together
any suggestions

#include <iostream>

int main()
{

using namespace std;
    int i;
    int a[5];
    int b[5];
    int array[10]= {1,2,3,4,5,6,7,8,9,0};


    for(i=0; i<5; i++){

        a[i]=array[i];

    cout << a[i];  // output = 12345
     }

    for(i=5; i<10; i++){

       b[i]=array[i];

    cout << b[i];  // output = 678910  
    }
    
    for(i=0; i<5; i++){

    cout<<a[i]<<" "<<b[i]<<"\n"; // output = 6 2293508
                                 //          7 2293560 
                                 //          8 2293728 
                                 //          9 2002919 
                                 //          10 20091472
	
    return 0;
}

What I want is output =
1 6
2 7
3 8
4 9
5 10

[Peter87]

The problem is that in the second loop you are accessing b[5] to b[9]. What you want is b[0] to b[4] so you have to adjust the index by doing subtraction.

[MrHutch]

for(i=5; i<10; i++)
{
  b[i] = array[i];
}

Careful!

for(i=5; i<10; i++)
{
  b[i-5] = array[i];
}

[peter hurley]

Thank you both for that I will try your coding.

[vlad from moscow]

To avoid such errors you can use standard algorithm std::copy

For example

#include <iostream>
#include <algorithm>

int main()
{
   const size_t N = 5;
   int a[N];
   int b[N];
   int array[2 * N]= { 1, 2, 3, 4, 5, 6, 7, 8, 9, 0 };


   std::copy( array, array + N, a );

   std::for_each( a, a + N, []( int x ) { std::cout << x; } );   
   std::cout << std::endl;

   std::copy( array + N, array + 2 * N, b );

   std::for_each( b, b + N, []( int x ) { std::cout << x; } );   
   std::cout << std::endl;
    
   for( size_t i=0; i < N; i++ )
   {
      std::cout << a[i] << " " << b[i] << "\n";	
   }

   return 0;
}

[peter hurley]

Thank you Peter87 & iHutch105 your suggestions together gave me the correct result.

I owe you both a few beers.

I will have a look at your coding vlad but I am better with nested loops.

[peter hurley]

Hi vlad

your coding did not compile ?

This is what I got:-

line 14 error: expected primary-expression before '[' token
line 14 error: expected primary-expression before ']' token
line 14 error: expected primary-expression before 'int'
line 19 error: expected primary-expression before '[' token
line 19 error: expected primary-expression before ']' token
line 14 error: expected primary-expression before 'int'

[peter hurley]

#include <iostream>

using namespace std;

int main()
{
    int i;
    int a[5];
    int b[5];
    int array[10]= {1,2,3,4,5,6,7,8,9,10};

    for(i=0; i<5; i++){
        a[i]=array[i];

    }

    for(i=5; i<10; i++){
        b[i-5]=array[i];

    }

    for(i=0; i<5; i++){

        cout <<a[i]<<" "<<b[i]<<"\n";
    }

    return 0;
}

output:-

1 6
2 7
3 8
4 9
5 10


Thank you

[scottramos18]

good