Member Avatar for bucsoldier03

i have to convert a program from c++ to C language and at one point in my program im stuck where its dealing with dynamic memory of an array. i started it but i dont know how u do dynamic memomory in c language.

if (reply == '1')
   {
      printf("Enter the 1st score (any invalid score to quit): ");
      scanf("%d", score);
      while (score >= 0 && score <= 100)
      {
         ++numOfScores;
         if (numOfScores > arraySize)
         {
            arraySize = int(1.5*arraySize + 1);
            scoresArrayPtrHold = scoresArrayPtr;
            scoresArrayPtr = new int [arraySize];
            for (int i = 0; i < numOfScores - 1; ++i)
               *(scoresArrayPtr + i) = *(scoresArrayPtrHold + i);
            free(scoresArrayPtrHold);
            scoresArrayPtrHold = 0;
         }
         *(scoresArrayPtr + numOfScores - 1) = score;

         printf("Enter the next score (any invalid score to end): ");
         scanf("%d", score);
      }
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  • Latest Post Latest Post by dwks

Dani AI

Generated

A few focused tips to convert that C++ snippet into clean C (and to avoid the common pitfalls seen in the thread).

  • As recommended, use the C allocation family (malloc / realloc / free). Do not mix C++ new with C free — use matching alloc/free or new/delete consistently. was right to point you to the man page, and 's reminder to free memory is important: always free what you allocate. and gave pointers to tutorials worth reading for background.

  • Use realloc to grow the buffer instead of allocating, copying, and freeing manually. Check scanf return values and pass the address (&score). Watch the off-by-one: check count >= capacity before inserting.

Example C pattern (safe, minimal checks):

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

int main(void) {
    int *scores = NULL;
    size_t capacity = 0, count = 0;
    int score;

    printf("Enter the 1st score (any invalid score to quit): ");
    while (scanf("%d", &score) == 1 && score >= 0 && score <= 100) {
        if (count >= capacity) {
            size_t new_capacity = capacity ? (capacity * 3) / 2 + 1 : 4;
            int *tmp = realloc(scores, new_capacity * sizeof *scores);
            if (!tmp) { free(scores); fprintf(stderr, "Out of memory\n"); return 1; }
            scores = tmp;
            capacity = new_capacity;
        }
        scores[count++] = score;
        printf("Enter the next score (any invalid score to end): ");
    }

    /* use scores[0..count-1] */

    free(scores);
    return 0;
}

Practical notes: always test allocation results, prefer size_t for sizes, avoid arithmetic that might overflow on very large arrays, and validate user input (check scanf return). Using realloc with a temporary pointer prevents leaks on failure. This approach should map cleanly from the C++ logic while following C conventions.

Recommended Answers

All 7 Replies

Member Avatar for WolfPack

search for the malloc, calloc, realloc functions.

Member Avatar for SpS

you'll find good tutorials on this site itself

Member Avatar for bucsoldier03

whats that

Member Avatar for bucsoldier03

how do i get to the tutoriols

Member Avatar for perniciosus

how do i get to the tutoriols

man is your friend...

(*hint man malloc)

Member Avatar for dwks

And don't forget free() , which I'm sure is mentioned in the tutorial.

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