Control Statement in c – else if block – C Language Tutorial

For video tutorial you can see below video:

The if-else is statement is an extended version of If. The general form of  if-else is as follows:

Flow diagram of if else statement:

When using if...else if..else statements, there are few points to keep in mind :-
     ✔An if can have zero or one else's and it must come after any else if's.
     ✔ An if can have zero to many else if's and they must come before the else.
     ✔ Once an else if succeeds, none of the remaining else if's or else's will be tested.

The general syntax of how else-if ladders are constructed in 'C' programming is as follows:

if(test-expression 1)      {

   Statement1;
} else if(test-expression 2) {
   Statement2;
} else if(test-expression 3) {
   Statement3;
} else if(test-expression n) {
   Statementn;
} else {
   default;
}
Statement x;

✔ This type of structure is known as the else-if ladder. This chain generally looks like a ladder hence it is also called as an else-if ladder. The test-expressions are evaluated from top to bottom. 
✔ Whenever a true test-expression if found, statement associated with it is executed. When all the n test-expressions becomes false, then the default else statement is executed.

Let us see the actual working with the help of a program.

#include<stdio.h>

#include<conio.h>

void main()

{

         int marks=83;

         clrscr();

         if(marks>75){

                 printf("First class");

         }

         else if(marks>65){

                 printf("Second class");

         }

         else if(marks>55){

                 printf("Third class");

         }

         else{

                 printf("Fourth class");

         }

         getch();

}

Output:

First class

✔ The above program prints the grade as per the marks scored in a test. We have used the else-if ladder construct in the above program.

👉   We have initialized a variable with marks. In the else-if ladder structure, we have provided various conditions.

👉   The value from the variable marks will be compared with the first condition since it is true the statement associated with it will be printed on the output screen.

👉   If the first test condition turns out false, then it is compared with the second condition.

👉   This process will go on until the all expression is evaluated otherwise control will go out of the else-if ladder, and default statement will be printed.

✔ Try modifying the value and notice the change in the output.

Summary:

      👉It is also called as control statements because it controls the flow of execution       of a program.

👉'C' provides if, if-else constructs for decision-making statements.
👉We can also nest if-else within one another when multiple paths have to be           tested.

✔ The else-if ladder is used when we have to check various ways based upon the result of the expression.