Thread: null an int[]

Hi there, I have been writing some code to convert a number in base x to base y. During the operations, I would like to null the integer array so I can re-use it, so I don't have to create another integer array.

Code:

int a[20];
/*give a some elements*/
a = NULL /*not allowed*/

Do I have to create a pointer to this array and use that the whole way through until it is time to null the pointer? Or is there a way do this? Forgive my ignorance, it seems like there should be an easy answer but I cannot find it by googling.

Thanks

ps: if you need my code:

Code:

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

#define SIZE 20

void toDecimal(int base, int num[], int len);
int toBase(int base,  int num, int a[]);
void reverseit(int a[],int len);
int arraytonum(int a[], int len);

int main(int argc, char *argv[]) {

  if(argc > 5 || argc < 3) {
    printf("Usage: base 2210 4 5 \n(2210 in base 4 to base 5)\n");
    exit(1);
  }

  char *num = argv[1];
  int number[SIZE];
  int anotherarray[SIZE];  /* i just want to null number[] and not use this */
  int length=0;
  while(*num) {
    number[length] = *num - '0';
    num++;
    length++;
  }

  int frombase = atoi(argv[2]);
  int tobase = atoi(argv[3]);
  toDecimal(frombase,number,length);
  int numero = arraytonum(number,length);

  /*number = NULL; (i wish to null it here) */

  int newlen = toBase(tobase,numero,anotherarray);
  reverseit(anotherarray, newlen);

  int j;
  for(j=0;j<newlen;j++) {
    printf("anotherarray[&#37;d]=%d\n", j, anotherarray[j]);
  }

  return 0;

}

void toDecimal(int base, int num[], int len) {
  int k;
  for(k=0;k<len;k++) {
    num[k] *= (int)pow(base,len-1-k);
  }
}

int toBase(int base, int num, int a[]) {
  int i=0;
  while( (num % base) != num ) {
    a[i] = num % base;
    num = (int)floor(num/base);
    i++;
  }
  a[i] = num;

  return i+1;
}

void reverseit(int a[], int len) {
  int i = 0;
  int temp;
  int loop = (int)floor(len/2);
  while(loop > 0) {
    temp = a[i];
    a[i] = a[len-1-i];
    a[len-1-i] = temp;
    loop--;
    i++;
  }
}

int arraytonum(int a[], int len) {
  int k;
  int num=0;
  for(k=0;k<len;k++) {
    num += a[k];
  }

  return num;
}

If you are using a static array of integers, I don't really see a need for you to use pointers here as you can just access what you want using the array index.

An int cant be set to NULL. That is for pointers. Similarly '\0' is null for chars. For ints just reset it to 0.

Okay, thanks for your replies guys, much appreciated.