Example:

#include <stdio.h>

int main()
{
	//declaring array, initialising with decimal values	
	unsigned char arr1[]={10, 20, 30, 40, 50};
	//declaring array, initialising with octal values	
	unsigned char arr2[]={010, 077, 023, 045, 057};		
	//declaring array, initialising with hexadecimal values	
	unsigned char arr3[]={0x10, 0xAA, 0x67, 0xA1, 0xFF};	
	int i;
	
	//printing the numbers
	printf("arr1...\n");
	for(i=0; i<5; i++)
		printf("%d ",arr1[i]);
	printf("\n");

	//printing the numbers
	printf("arr2...\n");
	for(i=0; i<5; i++)
		printf("%o ",arr2[i]);
	printf("\n");
	
	//printing the numbers
	printf("arr3...\n");
	for(i=0; i<5; i++)
		printf("%X ",arr3[i]);	
	printf("\n");
	
	return 0;	
}

Output

arr1...
10 20 30 40 50 
arr2...
10 77 23 45 57 
arr3...
10 AA 67 A1 FF