Decision making statements in C

Decision making statements simply make decisions on the execution of the program that which line has to be executed next.

Decision making statements are

• Simple if
• If else
• If else if else
• Nested if
• If else ladder

Simple if:

Syntax:

if(expression)

{

//true block;

}

Example Program:

#include<stdio.h>

void main()

{

int number=10;

clrscr();

if(number%2==0)

printf(“\n The given number is an Even number”);

getch();

}

Aim of this program is to find whether the given number is an even number.

Key idea: If the number is even, then it will definitely be divisible by 2. Whenever even number is divided by 2, then it will give the remainder as 0(zero).

To be known: if syntax, modulus operator(give the remainder)  

Program Explanation:

Include header file <stdio.h> for input output operations.

Declare the variable and initialize it to any number (I consider it as 10)

clrscr() – Clears the previous output from output screen

if(number%2==0)-checks whether the given number is divisible by 2

printf()-prints the statement if and only if the condition is true.

getch()-get character-->used to display output.

If  - else:

Syntax:

if(expression)

{

//true block;

}

else

{

//false block;

}

Example Program:

#include<stdio.h>

void main()

{

int number=10;

clrscr();

if(number%2==0)

printf(“\n The given number is an Even number”);

else

printf(“\n The given number is an odd number”);

getch();

}

Aim of this program is to find whether the given number is an even number or odd number.

Key idea: If the number is even, then it will definitely be divisible by 2. Whenever even number is divided by 2, then it will give the remainder as 0(zero).Otherwise it must be odd number.

To be known: if - else syntax, modulus operator(give the remainder)  

Program Explanation:

Include header file <stdio.h> for input output operations.

Declare the variable and initialize it to any number (I consider it as 10)

clrscr() – Clears the previous output from output screen

if(number%2==0)-checks whether the given number is divisible by 2

printf()-prints the statement if and only if the condition is true.

else – condition in if() is not true

 printf()-prints the statement if and only if the condition is false

getch()-get character-->used to display output.

 If - else if - else:

Syntax:

if(expression)

{

//true block1;

}

else if(expression)

{

//true block2;

}

else

{

//false block;

}

Example Program:

#include<stdio.h>

void main()

{

int number=10;

clrscr();

if(number>0)

printf(“\n The given number is Positive”);

else if(number<0)

printf(“\n The given number is Negative”);

else

printf("\n The given number is Zero");

getch();

}

Aim of this program is to find whether the given number is an positive or negative number.

Key idea: 

• If the number is positive, then it will be greater than 0(zero).
• If the number is negative, then it will be less than 0(zero).
• Otherwise it must be 0(zero).

To be known: if - else if- else syntax, operators 

Program Explanation:

Include header file <stdio.h> for input output operations.

Declare the variable and initialize it to any number (I consider it as 10)

clrscr() – Clears the previous output from output screen

if(number>0) – checks whether the given number is greater than 0(zero)

printf() – prints the statement if and only if the condition is true.

else if(number<0) – checks whether the number is less than 0(zero)-->executes only if(number>0) evaluates false

else – condition in both if() and else if() is false

 printf() – prints the statement if and only if both the expressions evaluates false

getch() – get character-->used to display output.