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carraysmalloc
Kyuu
Kyuu

Reputation: 1045

How to use malloc on a 2D integer array

How do I define a 2D array where the first dimension is already defined with MAX_VALUES. I wish to be able to allocate memory to the second dimension. Below is what I have attempted. I want an array with A[1000][mallocd]

#define MAX_VALUES 1000
int
main(){
    int n= 10;
    int *A[MAX_VALUES] = malloc(10 * sizeof(int));

}

Upvotes: 2

Views: 77

Answers (3)

Eugene Sh.
Eugene Sh.

Reputation: 18321

int *A[MAX_VALUES] is an array of int pointers, which is already statically allocated. If you want to allocate some space pointed by each one of the pointers you will have to iterate on the array and assign each pointer with a different malloc. Otherwise you will have to redefine your A (as @haccks answer is suggesting, for example).

Upvotes: 1

Sourav Kanta
Sourav Kanta

Reputation: 2757

try this :

int*A[MAX_VALUES],n;
for(i=0;i<MAX_VALUES;i++)
  A[i]=malloc(n*sizeof(int);

It will have MAX_VALUE rows with number of coloumns mallocked.

Upvotes: 1

haccks
haccks

Reputation: 106012

Try this 

int (*A)[n] = malloc(MAX_VALUES * sizeof(*A));

It will allocate contiguous 2D array.

Upvotes: 2

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