overview of c++ language
DESCRIPTION
Overview of c++ programming languageTRANSCRIPT
Overview of C++ language
Lecture’s outline
What is C++?Identifiers.ConstantSemicolons & Blocks in C++Data typeCommentsOperatorDeclaration of variablesGiving value to variableC++ statements
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What is C++?• Developed by Bjarne Stroustrup (in 1979 at Bell Labs)
• C++ is regarded as a middle-level language, as it comprises a
combination of both high-level and low-level language features.
• C++ is a statically typed, compiled, general purpose, case-
sensitive, free-form programming language that supports
procedural, object-oriented, and generic programming.
• C++ is a superset of C that enhancement to the C language and
originally named C with Classes but later it was renamed C++.
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identifiersThey are used for naming classes function, module,
variables, object in a program.
They follow the following rules:
1) They can have alphabets , digits, and the underscore(_).
2) They must not begin with a digit.
3) Uppercase and lowercase are distinct.
4) They can be of any length.
5) It should not be a keyword.
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6) White space is not allowed.
ConstantConstant is one whose value cannot be changed after it has been initialized-any attempt to assign to field will produce a compile-error .So, we can declare the constant by using const field and use all uppercase letter.
Syntax of declare the constant is:
Example:
const int STRENGTH = 100;const float PI = 3.14;
const type name=value
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Semicolons & Blocks in C++:• In C++, the semicolon is a statement terminator.
That is, each individual statement must be ended with a semicolon. It indicates the end of one logical entity.
• For example: following are two different statements:
x = y; y = y+1;
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Data type
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Comments
C++ can use both the single line comments and multi-line comments .single line comments begin with // and end at the end of line.For longer comments we can create multi-line comments by starting with /* and ending with */
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Operator* / % + - are the mathematical operators* / % have a higher precedence than + or – ++ Increment operator –– Decrement operator
== Equal (careful)!= Not equal>= Greater than or equal<= Less than or equal> Greater than< Less than&& logical (sequential) and || logical (sequential) or= assignment
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Logical operators
Relational operators
mathematical operators
Declaration of variables
The general form of declaration of variables:
Example:
int count;float x,y;double pi;char c1,c2,c3;byte b;
Type variable1, variable2,...., variableN;
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Giving value to variable
The general form of giving value to variables:
Example:
finalValue=100;x=y=z=0;Yes = ‘x’;
variableName= value;
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The general form of giving value to variables:
Example:
finalValue=100;x=y=z=0;Yes = ‘x’;
variableName= value;
Simple programs
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Write C++ Program to find Sum and Average of two numbers?
Write C++ Program to find area of a circle?
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C++ statement
Control statement
Selection statement
jump statement
iteration statement
If if-else switch for while do break continue return
• C++ supports the following statements Known as control or decision making statements.
1. if statement.2. switch statement.3. Conditional operator ? : statement.
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Decision making
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Decision making with if statement
The general form of simple if statement is :
Example:
if (a > b) cout<<"a > b";
if (<conditional expression>)<statement action>
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Decision making with if statement cont..
The general form of simple if else statement is :
Example:
if (a > b) cout<<" a > b"; else cout<<"a<b";
if (<conditional expression>)<statement action>else <statement action>
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Decision making with if statement cont..
The general form of Multiple if else statement is :
Example:if (a > b) cout<<" a > b"; else if (a< b) cout<<"b > a";else cout<<" a=b";
if (<conditional expression>)<statement action>else if (<conditional expression>)<statement action>else <statement action>
• The if statement allows you to select one of two sections of code to execute based on a boolean value (only two possible values). The switch statement allows you to choose from many statements.
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Decision making with switch statement
switch (expr) { case c1: statements // do these if expr == c1 break; case c2: statements // do these if expr == c2 break; case c3: case c4: // Cases can simply fall thru. statements // do these if expr == any of c's break; . . . default: // OPTIONALstatements // do these if expr != any above }
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Decision making with switch statement cont..
The ? : Operator:
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• can be used to replace if...else statements. It has the following general form:
Exp1 ? Exp2 : Exp3; Where Exp1, Exp2, and Exp3 are expressions. • The value of a ? expression is determined like this:
Exp1 is condition evaluated. If it is true, then Exp2 is evaluated and becomes the value of the entire ? expression. If Exp1 is false, then Exp3 is evaluated and its value becomes the value of the expression.
Simple programs
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Write C++ Program to find Number is Positive or Negative?
Write C++ Program to find the Grade of student ?
Write C++ Program to check the day of week by using SWITCH-CASE?
LoopingThe C++ language provides three constructs for
performing loop operations, there are:1. The for statement.2. The while statement.3. The do statement.
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Looping cont..The general form of for statement:
Example:for( x=0; x<=10; x++) {cout<<x;}
for (initialization; test condition; increment) { Body of loop }
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Looping cont..The general form of while statement:
Example:x=0;while(x<=10) {cout<<x;x++; }
initialization; while(test condition) { Body of loop }
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Looping cont..The general form of do statement:
Example:x=0;do{cout<<x;x++; }while(x<=10) ;
initialization; do { Body of loop } while(test condition);
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Nested Loopingfor(num2 = 0; num2 <= 3; num2++){ for(num1 = 0; num1 <= 2; num1++) { cout<<num2 << " " <<num1; }}
Int num1 Int num2
0 0
1
2
3 end of loop
0 1
1
2
3 end of loop
0 2
1
2
3 end of loop
0 3
1
2
3 end of loop
4 End of loop
Functions
• A complex problem is often easier to solve by dividing it into several smaller parts(Modules), each of which can be solved by itself. This is called structured programming.
• In C++ Modules Known as Functions & Classes• main() then uses these functions to solve the
original problem.
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Functions (cont..)
• C++ allows the use of both internal (user-defined) and external functions.
• External functions (e.g., abs, ceil, rand, sqrt, etc.) are usually grouped into specialized libraries (e.g., iostream, stdlib, math, etc.)
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Function prototype• The function prototype declares the input and
output parameters of the function.
• The function prototype has the following syntax: <type> <function name>(<type list>);
• Example: A function that returns the absolute value of an integer is: int absolute(int);
• If a function definition is placed in front of main(), there is no need to include its function prototype.
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Function Definition• A function definition has the following syntax:
<type> <function name>(<parameter list>){<local declarations> <sequence of statements> }
• For example: Definition of a function that computes the absolute value of an integer:
int absolute(int x){ if (x >= 0) return x; else return -x; }
• The function definition can be placed anywhere in the program. prepared by Taif.A.S.G 30
Function call
• A function call has the following syntax: <function name>(<argument list>)
Example: int distance = absolute(-5);
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