New topic: Conditionals
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Classwork:
Flowcharts: write a short code fragment for each of the following flowcharts:
if and if/else

while and for loops

More on conditionals with the slides on this link:

Assignments:

1. Write a more general and robust version of ComplexRootsQuad.java that prints the roots of the polynomial ax^2 + bx + c, prints real and complex solutions.
2. What (if anything) is wrong with each of the following statements?
   if (a > b) then c = 0;
   if a > b { c = 0; }
   if (a > b) c = 0;
   if (a > b) c = 0 else b = 0;
3. Write a code fragment that prints true if the double variables x and y are both strictly between 0 and 1 and false otherwise.
4. Write a program AllEqual_YI.java that takes three integer command-line arguments and prints equal if all three are equal, and not equal otherwise.
5. Rewrite TenHellos.java to make a program ManyHellos_YI.java that prompts the user for the consecutive lines to print… You may assume that the argument is less than 1000. Hint: consider using i % 10 and i % 100 to determine whether to use “st”, “nd”, “rd”, or “th” for printing the ith Hello.Example output:
   * Starting number? 4
   * Ending number? 8

   * 4th Hello
   * 5th Hello
   * 6th Hello
   * 7th Hello
   * 8th Hello

6. What is the value of m and n after executing the following code?

   int n = 123456789;
   int m = 0;
   while (n != 0) {
      m = (10 * m) + (n % 10);
      n = n / 10;
   }
   
   

7. What does the following code print out?

   int f = 0, g = 1;
   for (int i = 0; i <= 15; i++) {
      System.out.println(f);
      f = f + g;
      g = f - g;
   }
   
   

A site to check your understanding:

Classwork:
1. Write a more general and robust version of YI_Quadratic.java that prints the roots of the polynomial ax^2 + bx + c, prints an appropriate error message if the discriminant is negative, and behaves appropriately (avoiding division by zero) if a is zero.

1. What (if anything) is wrong with each of the following statements?
   if (a > b) then c = 0;
   if a > b { c = 0; }
   if (a > b) c = 0;
   if (a > b) c = 0 else b = 0;

2. Write a code fragment that prints true if the double variables x and y are both strictly between 0 and 1 and false otherwise.

Homework: Conditionals and loops
4. Write a program YI_AllEqual.java that takes three integer command-line arguments and prints equal if all three are equal, and not equal otherwise.

1. Rewrite YI_TenHellos.java to make a program YI_Hellos.java that takes the number of lines to print as a command-line argument. You may assume that the argument is less than 1000. Hint: consider using i % 10 and i % 100 to determine whether to use “st”, “nd”, “rd”, or “th” for printing the ith Hello.

2. What is the value of m and n after executing the following code?

int n = 123456789;
int m = 0;
while (n != 0) {
   m = (10 * m) + (n % 10);
   n = n / 10;
}

1. What does the following code print out?

int f = 0, g = 1;
for (int i = 0; i <= 15; i++) {
   System.out.println(f);
   f = f + g;
   g = f - g;
}