STRUCTURED PROGRAMMING C++ Standard Library

Content 2

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C++ standard library

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C++ standards streams

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C++ namespace

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Types of common errors

Objectives 3

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By the end you should recognize: 

Ability to use offered C++ codes in appended standard library

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Library that provides handling of input / output in programs

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Input / output streams (cin , cout, and cerr) and their functionality

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Classification of the outcome errors from programs

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Important programming skills that you will gain after this

programming course

Standard Library 4

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Rich collections of existing code that can be reused in your applications 

Common math calculations e.g. sqrt, pow …etc

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String / character manipulations

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Date / Time functions

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Input / output

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Error checking

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Provided as part of C++ development environment

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You can use their capabilities by referring to the corresponding header file that certain library defined in

iostream Library 5

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Part of the C++ Standard Library

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Provides a uniform way of handling input from and output to predefined sources

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Based on the concept of a "stream "

Streams 6

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Pre-connected input and output channels between a computer program and its environment when it begins execution

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A stream is an object where a program can either insert or extract

characters to or from it 

Streams are generally associated to a physical source or destination of characters 

a disk file, the keyboard, or the screen

Streams (cont.) 7

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Two types 

Input streams are used to hold input from a data producer, such as a keyboard, a file

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Output streams are used to hold output for a particular data consumer, such as a monitor, a file, or a printer

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Programmer only has to learn how to interact with the streams

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Details about how the stream interacts with the actual devices is left up to the environment or operating system

Streams (cont.) 8

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Standard Input Stream (cin)

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Standard Output Stream (cout)

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Standard Error Stream (cerr)

keyboard

cin cout

screen

cerr

program

cin and cout 9

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Think of cout as a variable that accepts all data bound for standard output

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Think of cin as a variable that accepts all data bound for standard input

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The cout and cin declarations and definitions are located in the header file “iostream”

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All of the Standard C++ libraries are wrapped in a single

namespace std “standard”

Namespaces 10

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A mechanism for logically grouping declarations and definitions into a common declarative region

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Problem 

It becomes harder to think of new names for functions and variables when your programs reach a certain size

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C++ has a single arena where all the names live

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All developers must be careful not to accidentally use the same names to avoid conflict

Namespaces (cont.) 11

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Solution 

the namespace keyword

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Each set of C++ definitions in a library or program is “wrapped” in a namespace

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You can create your own namespace that hold blocks of codes then can be accessed by any code inside or outside the namespace

Common Errors 12

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Syntax (compilation) Errors 

encountered during compilation

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occurs when an instruction does not follow the syntax rules of the

programming language 

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e.g. forgetting a semicolon

Logic (Semantic) Errors 

Not detected during compilation

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produces unintended or undesired results 

e.g. forgetting to initialize a sum variable

Common Errors (cont.) 13

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Runtime (Execution-time) Errors 

occurs during the execution of a program

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May sometimes cause the program to crash 

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e.g. division by zero

You must develop 3 skills 

Design

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Debug

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Trace