Member Avatar for YaelGD

Hi y'all!
I need to sort an input of integers, long as we wish (not defined, depending on the user), which ends up by -1, and print it to the screen sorted. I can't think of anything that is simple enough to use (a beginners level, all we learned in the 4 lectures that we had was to the loops level, nothing too complicated). I know how to do it with arrays, or lists etc., but not without it. Any suggestion?
Thanks

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A short practical note and a couple of small examples to make the ideas in this thread more concrete and help with edge cases.

If the input domain is fixed and small (digits 0..9 in this case) the usual approach is to tally frequencies for each key, then output each key the recorded number of times. That yields linear time in the number of inputs and uses only a small, predictable amount of extra storage. It is exactly what landed on; and raised the right higher-level concerns (scalability and confirming constraints), and 's point about whether separate variables are "really" an array is worth noting: syntactically separate scalars are not an array type in C, but they are functionally equivalent only for very small fixed domains.

A minimal "no-array" C-style sketch using separate counters:

#include <stdio.h>

int main(void) {
    int x;
    int c0=0, c1=0, c2=0, c3=0, c4=0, c5=0, c6=0, c7=0, c8=0, c9=0;

    while (scanf("%d", &x) == 1 && x != -1) {
        switch (x) {
            case 0: c0++; break;
            case 1: c1++; break;
            case 2: c2++; break;
            case 3: c3++; break;
            case 4: c4++; break;
            case 5: c5++; break;
            case 6: c6++; break;
            case 7: c7++; break;
            case 8: c8++; break;
            case 9: c9++; break;
            default: /* ignore or signal invalid input */ break;
        }
    }

    for (int i = 0; i < c0; ++i) printf("0\n");
    /* repeat for c1..c9 */
    return 0;
}

For contrast, the idiomatic and far shorter version uses an array of 10 counters:

int counts[10] = {0};
while (scanf("%d", &x) == 1 && x != -1)
    if (0 <= x && x <= 9) counts[x]++;
for (int d = 0; d < 10; ++d)
    for (int j = 0; j < counts[d]; ++j) printf("%d\n", d);

Notes and pitfalls: validate inputs (ignore or report values outside the allowed range), handle the empty-input case, and watch for very large counts if inputs are huge. If the allowed key range grows, prefer arrays or proper data structures; the separate-scalar approach quickly becomes unmaintainable. This keeps the thread’s practical constraints in view and aligns with the corrections and cautions offered by , and .

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Member Avatar for Ancient Dragon

If you have variables a, b and c it would be not too difficult with some if statements. But the more variables you have the greater difficulty to sort them without an array or linked list.

Member Avatar for Narue

>Any suggestion?
I'd suggest that you confirm the need to do this without any kind of list. This sounds more like make-work with unreasonable restrictions than a beginner's project. Since you claim that it's a beginner's project, it's more likely that you just didn't fully understand the requirements and have made it more complicated than it needs to be.

Member Avatar for YaelGD

Hello again!
I just wanted you to know that I solved it, I forgot a tiny detail that makes all the difference: I have to sort numbers from 0 to 9. That means that I can sum the times a number appears and print it from the lowest to the highest, according to the number of times it appeared. It actually has a name, called BUCKET SORT.
Hope that it will be useful anyway.
Cheers.

Member Avatar for ArkM

Hello again!
I just wanted you to know that I solved it, I forgot a tiny detail that makes all the difference: I have to sort numbers from 0 to 9. That means that I can sum the times a number appears and print it from the lowest to the highest, according to the number of times it appeared. It actually has a name, called BUCKET SORT.
Hope that it will be useful anyway.
Cheers.

Well, yet another triumph of the most fundamental programming principle: only even number of errors can produce correct result...
It's interesting:
1. Why you have decided that your task specifications have forbidden you array using?
2. Can you make a bucket sort without arrays, lists, trees and other data structures?

Member Avatar for YaelGD

Well, yet another triumph of the most fundamental programming principle: only even number of errors can produce correct result...
It's interesting:
1. Why you have decided that your task specifications have forbidden you array using?
2. Can you make a bucket sort without arrays, lists, trees and other data structures?

Well, first, I didn't decide so, my tutor did :-)
second, you CAN use bucket sort. I guess that's the name of it... You know what your variables are, you just don't know how many times the user will print them, if any.
I have 10 variables, names zero_counter, one_counter,..., nine_counter, all initialized to zero, every time the user prints a legal number in that range, the compatible counter increases. You already know the order between them, all that's left to do is to print zeros the number of times needed, according to the zero_counter value (if zero_counter equals 0, you don't need to print zeros at all, obviously...), continue doing that to the one_counter, etc.
It's like you Do have a data structure of some kind, just not as one unified unit (not an array, a list etc.).
Still wanna prove me wrong? :-)

Member Avatar for jephthah

this will end well.

:|

Member Avatar for Narue

>Still wanna prove me wrong? :-)
You're still using an array, just without the convenience of array notation or the convenience of semantic guarantees that an array provides. Given a strict definition of "no arrays", your solution is invalid.

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