Can you print an array in reverse order without the need of a Loop/Array?

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Well, the simple answer is yes. Let me simplify it for you at first.. How can you print from 1 to n without using a loop?

By repeating this line 1000 times, Your program works just as efficiently as if you made an iterative loop from 1 to 1000.

 cout << x++ << endl;
  if(x==n)return 0;

For example, this code can print you numbers from 1 to 10.. You can develop it up to 1000

    int n,x=1;
    cin >> n; n++;
    cout << x++ << endl; // 1
    if(x==n)return 0;
    cout << x++ << endl; // 2
    if(x==n)return 0;
    cout << x++ << endl; // 3
    if(x==n)return 0;
    cout << x++ << endl; // 4
    if(x==n)return 0;
    cout << x++ << endl; // 5
    if(x==n)return 0;
    cout << x++ << endl; // 6
    if(x==n)return 0;
    cout << x++ << endl; // 7
    if(x==n)return 0;
    cout << x++ << endl; // 8
    if(x==n)return 0;
    cout << x++ << endl; // 9
    if(x==n)return 0;
    cout << x++ << endl; // 10
    if(x==n)return 0;

Input : 6 Output : 1 2 3 4 5 6

Well here comes the big question.. How do we print an array in reverse without using a loop? Well simply by reading the variables in ascending order and printing them in descending

Here is a small example on 5 variables:


        int n; cin >> n; //Number of Elements (Size of the array)
	int x1; cin >> x1;
	if (n == 1) goto line1;
	int x2; cin >> x2;
	if (n == 2) goto line2;
	int x3; cin >> x3;
	if (n == 3) goto line3;
	int x4; cin >> x4;
	if (n == 4) goto line4;
	int x5; cin >> x5;
	if (n == 5) goto line5;

line5: cout << x5 << ' ';
line4: cout << x4 << ' ';
line3: cout << x3 << ' ';
line2: cout << x2 << ' ';
line1: cout << x1 << ' ';

Input: 1 4 6 10 17 Output: 17 10 6 4 1

You can do the same thing up to 1000 elements or more..believe it or not, I solved some problems related to Arrays/Loops in this way.. And It Worked (Accepted✅)

Comments (10)

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chromate00

2 years ago, # |

sorry, but actually I think the real expected answer was recursion, you can read the value, call the next recursion first, and then output the variable. Same logic as preorder/inorder/postorder.

→ Reply

h1a4c3k

Why not recursion?

long long recur(long long n){
   cout << n << "\n";
   if(n <= 1) return 0;
   return recur(n-1);
}

int main(){
   long long n; cin >> n;
   recur(n);
   return 0;
}

I don't really know if this is a scam blog or not but I answered it anyway.

TryOmar

I really don't know why everyone is down-voting me.. I see it as a creative idea.. I really solved a problem with it asking me to reverse and array (and I solved it without an array/loop), and another problem asking me about printing numbers from 1 to n (and I solved it without a loop)

2 years ago, # ^ |

It is not a creative idea: What if n = 1e18? Would you love to copy-and-paste 1e18 times?

FatihCihan

lol if n = 1e18 you cannot store them in a array nor print them , it will take 1e9 seconds(~32 years)

← Rev. 17 →

it is not creative and usable , since you can just reverse(array.begin() , array.end()); idk why would someone do that in a contest or a interview

At least you can learn something from me is that you can take advantage of programming to write another code with repetitive lines like this

	for (int i = 0; i < 10; i++)
	{
		cout << "cout << x++ << endl;\n";
		cout << "if (x == n)return 0;\n";
	}

dont get me wrong but these are really common features , everyone uses them , maybe you should check other people's code before writing something like this idk

Can you give me an example please?

like for example , we use for loop to do repetative tasks for(int i = 0;i<n;i++)do_something(); you dont need to use goto or other weird and unnecesarily complicated things like that , it will slow you

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