1/5 Class Notes

Homework: https://docs.google.com/forms/d/e/1FAIpQLScH8YbvVv1uYnJsa4XtecECADk0RZFmA4tWWxLQ67R_nrB9pw/viewform?usp=sf_link

Do loop:

• do loop example:

int count = 0;

do

{

count++;

System.out.println(count);

}

while (count <5);

Nested loops:

• Similar to nested for statements, while loops and do loops can be nested as well

  • "Nested" means the inner loop must complete reside in the outer loops - no overlapping

• For each iteration of the outer loop, the inner loop iterates completely
  

How to hand trace a program for debugging:

• Your code will go wrong so debugging and testing are always needed

• You can debug (troubleshoot) by:

  • Hand tracing

  • Adding print statements to your code

  • Adding testing methods to the class

• Hand tracing (tracing by hand) is a simulation of code execution in which you step through statements and tack the values of certain variables. It is effective with a short program or part of a method. When you hand trace code or pseudocode, you write the names of the variables on a sheet of paper, mentally execute each step of the code, and update the variable values accordingly.

• When you use print statements for debugging, you insert print statements at key locations to show values of significant variables and how far your code got before there was a problem. In the print statement, it is a good idea to specify the location of the trace (what method) and the variable name and its value.

• All Integrated Development Environments (IDE) such as Eclipse have an interactive debugger feature. You can single-step step through your code (one statement at a time), see what is stored in variables, set breakpoints, and watch a variable or expression during execution.

Phases of Programming

• A typical programming task can be divided into multiple phases

  • Analyzing and solution design phase: Analyze the problem to understand data and constraints, produce an ordered sequence of steps that describe the solution of a problem

    • This sequence of steps is called an algorithm

  • Implementation phase: implement the program in some programming language

  • Debugging and testing phase: test the program thoroughly, debug and resolve defects

• Steps in Solution design phase

  • Produce a general algorithm

    • You can use pseudocode (pseudocode is an artificial and informal language that helps programmers develop algorithms, it is very similar to everyday English)

  • Refine the algorithm successively to get a step by step detailed algorithm that is very close to a computer language

  • Turn pseudocode into flowchart to verify the designed solution works correctly in all cases
    

Flowchart

• A schematic representation of the algorithm or problem-solving process

• A graphical representation of the sequence of operations in a program (it can have different levels of granularity)

  • Shows logic of an algorithm

  • Emphasizes individual steps and their interconnections

• Different symbols are used to draw each type of flowchart