CODEWITHSUNDEEP
carraysdynamicdynamic-memory-allocation
Isan Rivkin
Isan Rivkin

Reputation: 167

How to create live dynamic memory allocation in an array of numbers, while taking input?

So My mission is to keep accepting numbers from users until the user input a negative number. My algorithm should be: 1)start in the size of 2. 2)double the size every time it reaches the end, free the older one. 3) stop when user hits negative number.

**I know I haven't used free and didn't check if the allocation is successful, I'm trying to keep the code as clean as possible for you guys. Please help.

#include <stdio.h>
#include <stdlib.h>
int *reallocate(int* numbers,int i,int arr[]);
int main() {
    int numbers[2];
    int *nums = numbers;
    int i = 0;
    int size = 2;
    while (i<size)
    {
        scanf("%d", (nums+i));
        if (*(nums + i) <0)
            break;
        i++;
        if (i == size) {
        nums=reallocate(nums,i,numbers);
        size = size * 2;
        }
    }
    puts("Stop");
    return 0;
}
int *reallocate(int* numbers,int i, int arr[]) {
    int newsize = 0;
    newsize =i * 2 * sizeof(int);
    numbers = (int *)realloc(arr,newsize);
    return numbers;
}

Upvotes: 0

Views: 49

Answers (1)

stek29
stek29

Reputation: 395

You should use malloc'ed arrays only with realloc
Here is code:

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    int *nums;
    size_t size = 2;
    nums = malloc(size * sizeof(int));
    size_t i = 0;

    while (i < size && nums != NULL) {
        scanf("%d", (nums+i));
        if (nums[i] < 0)
            break;
        i++;
        if (i == size) {
            size *= 2;
            nums = realloc(nums, size * sizeof(int));
        }
    }

    if (nums == NULL) {
        puts("Error");
        return 1;
    } else {
        free(nums);
        puts("Stop");
        return 0;
    }
}

Upvotes: 1

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