Find the errors in the following code: 

1. // This code contains ERRORS!
// It adds two numbers entered by the user.
int num1, num2;
String input;
char again;
Scanner keyboard = new Scanner(System.in);
while (again == 'y' || again == 'Y')
 System.out.print("Enter a number: ");
 num1 = keyboard.nextInt();
 System.out.print("Enter another number: ";

num2 = keyboard.nextInt();
 System.out.println("Their sum is "+ (num1 + num2));
 System.out.println("Do you want to do this again? ");
 keyboard.nextLine(); // Consume remaining newline
 input = keyboard.nextLine();
 again = input.charAt(0);

2. // This code contains ERRORS!
int count = 1, total;
while (count <= 100)
 total += count;
System.out.print("The sum of the numbers 1 - 100 is ");
System.out.println(total);

3. // This code contains ERRORS!
int choice, num1, num2;
Scanner keyboard = new Scanner(System.in);
do
{
 System.out.print("Enter a number: ");
 num1 = keyboard.nextInt();
 System.out.print("Enter another number: ");
 num2 = keyboard.nextInt();
 System.out.println("Their sum is " + (num1 + num2));
 System.out.println("Do you want to do this again? ");
 System.out.print("1 = yes, 0 = no ");
 choice = keyboard.nextInt();
} while (choice = 1)

4. // This code contains ERRORS!
// Print the numbers 1 through 10.
for (int count = 1, count <= 10, count++;)
{
 System.out.println(count);
 count++;
}