text: #include<stdio.h>
  #define MAXSIZE 100
  
  /*Given a non-empty array of integers nums,
   * every element appears twice except for one.
   * Find that single one.  */
  
  int main()
  {
  	int nums[MAXSIZE];
  	int number, x;
  
  	/*input data*/
  	printf("The program is used to check if there is a single digit!\n");
  	printf("Please enter the number of digits: ");
  	scanf("%d", &number);
  	printf("Please enter the digits(number+1): ");
  	for (int i = 0; i <= number; i++)
  	{
  		scanf("%d", &nums[i]);
  	}
  
  	/*XOR*/
  	x = nums[0];
  	for (int j = 1; j <= number; j++)
  	{
  		x = x ^ nums[j];
  	}
  	if (x == 0)
  		printf("There is no single digit in the number entered!");
  	else 
  		printf("A single number is %d", x);
  	return 0;
  }
  
  