if else statement condition

Condition - is the state of an expression or a variable; for example, when a result can be either true or

                false, or not equal.

if else statement – this is a control statement that executes a block of code.

                Syntax:

                                if (condition)

                                                statement1;

                                else

                                                statement2;

scanf(); used to read information from the keyboard

scanf(“%f”)  float, scanf(“%c”) character & symbol

clrscr(); -is used to clear the text mode window or to clean the output screen before running a program.

=============================================================================

This program will input 2 numbers, using the ”if else statement”  you can use this following

operators ( +, -, /, *)

//Sample Program1:

#include<stdio.h>

#include<conio.h>

main()

{

int invalid_operator=0;

char oprtor;

float num1, num2, result;

printf(Enter two numbers and an operator?\n");

printf("number1 operator number2\n");

scanf("%f %c %f",&num1,&oprtor,&num2);

                 if(oprtor=='*')

                                                result=num1 *num2;

                 else if (oprtor=='/')

                                                result=num1/num2;

                 else if (oprtor=='+')

                                                result=num1+num2;

                 else if (oprtor=='-')

                                                result=num1-num2;

                 else

                                invalid_operator=1;

                                if(invalid_operator!=1)

                                printf("%f %c %f is %f\n",num1,oprtor,num2, result);

                                else printf("invalid operator");

getche();

return 0;

}

Sample output:

Enter two numbers and an operator

number1 operator number2

4.0000 + 2.0000 is 6.0000

Enter two numbers and an operator

number1 operator number2

4.0000 * 2.0000 is 8.0000

Variable Declaration

Variable – refers to the named area in memory that stores a value or string assigned to that variable.

Ways to declare variable:

Global variable – outside of all functions, including the main() function

Local variable – inside a function; variables may only be used by statements that are in the same

 functions

Formal parameters

Data type – a set of data that specifies the possible range values of the set, the operations that

can be performed on the values, and the way in which values are stored in memory.

clrscr(); -is used to clear the text mode window or to clean the output screen before running a

program.

Data type	Control String	Description	Example
Char	“%c”	used for outputting letter or symbol	‘w’, ‘y’
Char	“%s”	used for outputting 2 or more letters or symbols and alphanumeric	‘Melo’, ‘P103’, ‘prof_melo’
Int	“%d”	used for outputting  whole numbers	8, 12, -5, 12854
Float	“%f”	used for outputting number  w/ decimal places	8.12, 16.09, -23.812
Double	“%f”	used for outputting larger number w/ or without decimal places	81256381225, 1276812.83

                                                                                                                                       

Operator – is a symbol that tells the compiler to perform specific mathematical or logical manipulations

+	Addition
-	Subtraction
*	Multiplication
/	Division
%	Modulus of remainder
Div	Integer division
Mode	Integer remainder
++/--	Increment and decrement

Relational operators – are used to determine the relationship of one quantity to another.

<	Less than
<=	Less that or equal to
>	Greater than
>=	Greater than or equal to
==	Equal to
!=	Not equal to
=	Assignment operators

Logical operators – are used to show the ways through which these relationships can be connected.

&&	AND
||	OR
!	NOT

==========================================

This program will compute the general average.

#include<stdio.h>

#include<conio.h>

main()

{

int pgrade, mgrade, sfgrade, fgrade, gaverage;

float avrage;

printf("\nEnter your Grade");

printf("\nPrelim Grade  => ");scanf("%d",&pgrade);

printf("Midterm Grade => ");scanf("%d",&mgrade);

printf("S_final Grade => ");scanf("%d",&sfgrade);

printf("Final Grade   => ");scanf("%d",&fgrade);

 gaverage=pgrade+mgrade+sfgrade+fgrade

 avrage=gaverage/4;

printf("\nGeneral Average => %.2f",avrage);                         //%.2f numbers w/ 2 decimal places

getche();

return 0;

}

Sample output:

Enter your Grade

Prelim Grade    => 89

Midterm Grade => 89

S_final Grade   => 89

Final Grade      => 89

General Average =>  89

Parts of Computer System

Computer system in contemporary usage refers to a desktop system, including the computer itself ("The CPU" or "The Box") and all the peripheral devices needed to operate it, usually including:

Monitor

A monitor displays information in visual form, using text and graphics. The portion of the monitor that displays the information is called the screen. Like a television screen, a computer screen can show still or moving pictures.

There are two basic types of monitors: CRT (cathode ray tube) monitors and LCD (liquid crystal display) monitors.