dynamic array malloc()
This code requests some heap memory with the initial buffer size of 10.
If the user enters 10 or less items, I'm ok.
but let's say he enters 4. Although I free() the array later on, I think wasted some memory because I had malloc() with size 10 already.
I know if I go over 10, the program will give me garbage.
How can I avoid setting up the initial buffer size?
How can I make an array truly dynamic? I just initiate with size 1, if I have more entries, the array expands automagically.
Code:#include <stdio.h> #include <stdlib.h> #include <ctype.h> #define STARTOFF 10 int main (void){ double *numbers; double *temp_nums; int i = 0; char response; int count; numbers = (double *)malloc(STARTOFF * sizeof(double)); if (numbers == 0){ printf("Out of memory!\n"); exit(1); } printf("Do you want to enter a number (y/n)? "); response = getchar(); while (toupper(response) == 'Y'){ printf("Enter a number: "); scanf("%lf", &numbers[i]); i++; fflush(stdin); printf("Do you want to enter a number (y/n)? "); response = getchar(); } count = i; temp_nums = (double *)malloc(count * sizeof(double)); for (i = 0; i < count; i++){ temp_nums[i] = numbers[i]; } free(numbers); numbers = temp_nums; free(temp_nums); printf("\nNumbers entered"); for (i = 0; i < count; i++){ printf("\n%.2f", numbers[i]); } printf("\n"); return 0; }
Originally Posted by Adak
