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INSIDE THE SERIES
The key features of the series have been designed to ensure better learning, assessment
and evaluation.
Learning Resources
Your Aim: This section Tech Funda: This section
describes the objective of provides a practical information
3 the chapter. or tip to the students.
INPUT AND OUTPUT
IN C++
statements is the statement block, that is to be repeatedly executed until the provided
condition becomes false.
Your Aim Tech Funda
to learn about:
Output Input Do not put a semicolon (;) after the closing parenthesis of a for loop. If you do,
the loop will keep running but will not execute any statements until the condition
Escape Sequence Characters Comments becomes false.
Every program requires some input to work and displays some output after processing the input. Program 1: To print first 10 natural numbers.
C++ also allows you to give input to a program and get the output from the program. Every
#include<iostream.h>
input/output in C++ is considered a stream of characters. C++ provides two objects to take the DOSBox 0.74, Cpu speed: max 100%
Declaration
input and to display the output, which are cin and cout. Let us discuss these in detail. #include<conio.h> 1 2 3 4 5 6 7 8 9 10
Before using a function, you need to declare it. Declaring a function is called function prototyping. void main()
OUTPUT
A function prototype tells the compiler about the data type and parameters of the function. The {
syntax to declare a function in C++ is:
The cout object is used to display output on a computer screen (monitor). It is part of the int i;
ostream class and is also known as the Standard Output Stream. The cout object works with clrscr();
return_type function_name([parameter 1, parameter 2, …]);
Where, the return_type specifies the data type of the value returned by the function. If no value
the stream insertion operator (<<) to show messages or values.
Program 6: To print the alphabet Using a Function.
is returned, the function should be declared with void. The function_name is the assigned name for(i = 1; i <= 10; i++)
For example: { DOSBox 0.74, Cpu speed: max 100% cycles, Frameskip 0, Program:
#include <iostream.h>
used to define and call the function later. Parameters are placed inside parentheses () and act as
placeholders for input values. The declaration must end with a semicolon (;). cout<< i << " "; Alphabets from A to Z:
cout<<"Output on the screen";
#include <conio.h>
void printAlphabets();
int display(int);
The above statement displays the message Output on the screen on the monitor. The stream } A B C D E F G H I J K L M N O P Q R S T U V
W X Y Z
void main()
In the above example, the display function is declared with int data type and and an int parameter.
insertion operator can be used multiple times in a single statement to combine and display getch();
{
Definition
multiple outputs. For example:
} clrscr();
cout<< “Alphabets from A to Z:\n”;
After declaring a function, you need to define it. Defining a function means to give the body of
cout<<"Hello"<<" from "<<" C++"; Using Comma (,) Operator with for Loop
printAlphabets();
the function. The definition of a function contains the functionality of the function in within curly
cout<<x; Clickipedia: This section C++ allows the use of the comma operator (,) to combine multiple expressions in a loop. When
You can also print the variable value using the cout object. For example:
Recap: This section provides
getch();
braces{ }. Let us consider the preceding example of display function:
}
int display(int age) two or more variables are used to control the loop, they are separated by the comma operator.
cout<<120; void printAlphabets()
{ provides interesting The comma operator allows: multiple initializations, multiple conditions and multiple counter
{
Chaining insertions is particularly useful when combining literals and variables in a single variables. a summary of the chapter for
cout<<”Your age is: “ << age <<” years.”;
return 0;
statement. For example: char letter;
computer facts.
quick recapitulation.
for (letter = ‘A’; letter <= ‘Z’; letter++)
}
cout<<"I am"<< name<<". I am"<<age<<" years old."; Program 2: To use the comma operator in for loop.
{
In the preceding code, you can see that the return statement is used before the ending curly
cout<< letter << “ “;
In the above statement, the values of the variables name and age are printed along with text, #include<iostream.h> DOSBox 0.74, Cpu speed: max
brace of the function to return an integer value. Because, the return type of the function is int.
}
producing an output like: #include<conio.h> i = 1, j = 10
The return is jump statement in C++ that transfers the control to the calling function. If you do i = 2, j = 9
}
not want to return any value from the function, then you need to declare a function with the void
I am Chirag. I am 18 years old. void main() i = 3, j = 8
data type. In this case, the function returns 0 (zero). { Recap i = 4, j = 7
24 i = 5, j = 6
Touchpad MODULAR (Ver. 2.0)-X clrscr();
Clickipedia
i = 6, j = 5
A function is a block of organized and reusable code used to perform a particular task.
int i, j; i = 7, j = 4
Built-in functions are predefined functions provided by C++.
C++ allows you to create your own functions which are known as user-defined functions.
The default return type of every function in C++ is int. for(i = 1, j = 10; i <= 10; i++, j--) i = 8, j = 3
i = 9, j = 2
The parameters passed at the time of declaring a function are called formal parameters.
i = 10, j = 1
{ There are two methods to call a function: call by value and call by reference.
The scope of a variable means how different parts of the program can access that variable.
Calling a Function cout << "i = " << i << ", j = " << j << endl;
Calling a function means to use the function for performing the desired task. To call a function,
you just need to write the name of the function with arguments, if any, in the parenthesis. The 60
arguments are the actual parameter’s values. Generally, a function call occurred inside the main() Touchpad MODULAR (Ver. 2.0)-X Exercise
function. However, you can call a function anywhere in the program.
A. Tick ( ) the correct option.
1. Which of the following is a block of code to perform a particular task?
a. Function c. Operator
86 b. Header file d. None of these
Touchpad MODULAR (Ver. 2.0)-X
2. Predefined functions are called ……………………. functions.
a. Built-in c. User-defined
b. Both a and b d. None of these
93
Functions in C++
Keyboard Shortcuts: This Explore More: This section Glossary: This section
section (in IV to X) contains contains supplement topics for contains definition of
keyboard shortcuts to perform add-on knowledge. important IT terms.
different operations.
Keyboard Shortcuts
C++ Subject Enrichment
Shortcut Keys Description
F2 To save a program
F3 To open a program
F10 To go to on the menu bar
Alt + Backspace To undo the previous action
Shift + Alt + Backspace To redo the previous undo
Shift + Del To cut the code
Ctrl + Insert To copy the code
Shift + Insert To paste the code
Ctrl + Delete To clear the screen
Ctrl + F9 To run a program
Alt + F9 To compile a program
Alt + Enter Toggle screen mode (full screen/ window)
Alt + F7 To go to on the previous error
Alt + F8 To go to on the next error
Alt + X To quit the Turbo C++ window
Keyboard ShortcutsKeyboard Shortcuts 111 111

