Initializing arrays

[volgadev]

Hello,

I am completely new to C programming. I use to be a Java programmer but I need to write a program in C. I am looking for a way to initialize an array with a computed length and didn't find any example in all the tutorials I found. The problem could be simplified to the following : ask the user to enter the length of the array, intialize the array to that length. How can one intialize an array with a length that is unkown at compile time ?

 

[marsd]

Simply.

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

#define MAX 1000000
#define MIN 1

int main(void) {
int len;
char *ptr;

                while (1) {   
                   printf("Please enter length of array: ");
		   scanf(" %d",&len);
		   if (len < MIN || len > MAX) {return -1;}
		   if( (ptr = malloc(len * sizeof(len))) == NULL) {
		       printf("Could not malloc() for array\n");
		       return -1;
                   }
		   printf("Memory at %p\n",ptr);
		   free(ptr);
                  }
return 0;
}

 

[jstreich]

int n;
//get value of n from user
int array[n];

Or am I missing something?
Is he trying to resize an array?

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[marsd]

Initializing an array as jstreich in a function doesn't accomplish anything if you want results in main().
Thus my example.

 

[volgadev]

Thank you very much for your help. As I need to create the array in a function and access it in main, I guess I must use the solution proposed by marsd. Thanks again ! (I see that I have much to learn in C !)