Lesson 4.2 5th and 6th step

Introduction to Programming in C++
Eight Edition
Lesson 4.2:
5th step : Desk Check

An Introduction to Programming with C++, Eight Edition
• Fifth step is to desk-check the program to make sure
instructions were translated correctly
• You should desk-check the program using sample data
used to desk-check the algorithm
• Results of both desk-checks should be the same
• First, place names of the declared memory locations in a
new desk-check table along with each memory location’s
initial value
• Next, desk-check remaining C++ instructions in order,
recording any changes made to the variables
Step 5–Desk-Check the Program
2

(cont’d.)
3

(cont’d.)
4

• Final step in the problem-solving process
• You evaluate a program by running the program on the
computer and entering the sample data used when desk-
checking the program
• If evaluation reveals errors (known as bugs), they must
be fixed
• Process of locating and fixing errors is called debugging
• Two types of bugs: syntax errors and logic errors
Step 6–Evaluate and Modify the
Program
5

• Syntax errors result from breaking programming
language’s rules; cause compiler errors
• Logic errors don’t cause compiler errors; can be hard to
identify – Example: entering instructions in the wrong
order
• Need a text editor to enter C++ instructions
• Instructions are called source code and are saved in
source files with extension .cpp
• Need a compiler to translate source code into machine
code (also called object code)
Program (cont’d.)
6

• Compiler saves object code in object files with
extension .obj
• Linker combines .obj files with other machine code
necessary to run the program and produces an executable
file with extension .exe
• An IDE (integrated development environment) is a
development tool that contains both an editor and
compiler
• A command-line compiler contains only the compiler
and requires a separate editor to enter source code
Program (cont’d.)
7

• A comment is a form of internal documentation;
written by placing // in front of the comment text
– Ignored by the compiler
– Considered good programming practice; makes code
more readable
• A #include directive allows you to merge the source code
in one file with that in another file
• The #include <iostream> is required when using the cin
or cout stream objects
– Not a statement, so no semicolon needed at the
end
Program (cont’d.)
8

• A using directive tells the compiler where in internal
memory it can find definitions of C++ keywords and
classes like double or string
• The using namespace std; directive indicates that the
definitions of the standard C++ keywords and classes are
located in the std (standard) namespace
– Is a statement, so semicolon required at the end
• A namespace is a special area in internal memory
Program (cont’d.)
9

• A function is a block of code that performs a task
• Functions have parentheses following their name
(Example: main())
• Some functions require information between the
parentheses; others do not
• Every C++ program has one (and only one) main
function; this is where program execution begins
• Some functions return a value, and the data type they
return appears to the left of the function name
– Example: int main()
Program (cont’d.)
10

• Other functions do not return a value, and void appears
to the left of the function name
• The return type, name, and parameters (information in
parentheses) constitute the function header, which marks
the beginning of the function
• After the function header, you enter the function’s code
• You enclose a function’s code in a set of braces ({})
• The code between the braces is called the function body
Program (cont’d.)
11

The sample program based on the
Figure 4-21
12

The output displayed in command
prompt
13

The End ♥ ♥ ♥
14

Lesson 4.2 5th and 6th step

More Related Content

What's hot (19)

Similar to Lesson 4.2 5th and 6th step (20)

More from MLG College of Learning, Inc (20)

Recently uploaded (20)

Lesson 4.2 5th and 6th step