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I am working on an application were there are three possible sizes for the data entered:
The problem is that I can't allocate the large array. It seems that a size larger than 5000 is not accepted.
I get a run time error when I do the following:
long size=1000;
char ch;
int arr[size];
ch=getch();
if(ch==..)
size=...;
Sizes of 1000 and 5000 seem to work fine, but how can I make an array of size 500k in this way?
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To allocate memory for an array, just multiply the size of each array element by the array dimension. For example: pw = malloc(10 * sizeof(widget));
Allocate an array with code>newint* a = NULL; // Pointer to int, initialize to nothing. int n; // Size needed for array cin >> n; // Read in the size a = new int[n]; // Allocate n ints and save ptr in a.
Statically declared arrays are allocated memory at compile time and their size is fixed, i.e., cannot be changed later. They can be initialized in a manner similar to Java. For example two int arrays are declared, one initialized, one not. Static multi-dimensional arrays are declared with multiple dimensions.
In this tutorial, you'll learn to dynamically allocate memory in your C program using standard library functions: malloc(), calloc(), free() and realloc(). As you know, an array is a collection of a fixed number of values. Once the size of an array is declared, you cannot change it.
You can allocate such a big array on the heap:
int *arr;
arr = malloc (sizeof(int) * 500000);
Don't forget to check that allocation succeded (if not - malloc returns NULL).
And as pmg mentioned - since this array is not located in the stack, you have to free it once you finished working with it.
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