When an if statement is placed inside another if statement it is known as this type of statement?

Conditional Statements in C programming are used to make decisions based on the conditions. Conditional statements execute sequentially when there is no condition around the statements. If you put some condition for a block of statements, the execution flow may change based on the result evaluated by the condition. This process is called decision making in ‘C.’

In ‘C’ programming conditional statements are possible with the help of the following two constructs:

1. If statement

2. If-else statement

It is also called as branching as a program decides which statement to execute based on the result of the evaluated condition.

In this tutorial, you will learn-

If statement

It is one of the powerful conditional statement. If statement is responsible for modifying the flow of execution of a program. If statement is always used with a condition. The condition is evaluated first before executing any statement inside the body of If. The syntax for if statement is as follows:

if [condition] instruction;

The condition evaluates to either true or false. True is always a non-zero value, and false is a value that contains zero. Instructions can be a single instruction or a code block enclosed by curly braces { }.

Following program illustrates the use of if construct in ‘C’ programming:

#include int main[] { int num1=1; int num2=2; if[num1= greater than or equal to

== equal to

!= not equal to

Notice that the equal test [==] is different from the assignment operator [=] because it is one of the most common problems that a programmer faces by mixing them up.

For example:

int x = 41; x =x+ 1; if [x == 42] { printf["You succeed!"];}

Output :

You succeed

Keep in mind that a condition that evaluates to a non-zero value is considered as true.

For example:

int present = 1; if [present] printf["There is someone present in the classroom \n"];

Output :

There is someone present in the classroom

The If-Else statement

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

if [test-expression] { True block of statements } Else { False block of statements } Statements;

n this type of a construct, if the value of test-expression is true, then the true block of statements will be executed. If the value of test-expression if false, then the false block of statements will be executed. In any case, after the execution, the control will be automatically transferred to the statements appearing outside the block of If.

Following programs illustrate the use of the if-else construct:

We will initialize a variable with some value and write a program to determine if the value is less than ten or greater than ten.

Let’s start.

#include int main[] { int num=19; if[num= 5] y = 5; else y = x; */ printf["y =%d ",y]; return 0;}

Output :

y =2

Nested If-else Statements

When a series of decision is required, nested if-else is used. Nesting means using one if-else construct within another one.

Let’s write a program to illustrate the use of nested if-else.

#include int main[] { int num=1; if[num75]{ printf["First class"]; } else if[marks>65]{ printf["Second class"]; } else if[marks>55]{ printf["Third class"]; } else{ printf["Fourth class"]; } return 0; }

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.

1. We have initialized a variable with marks. In the else-if ladder structure, we have provided various conditions.
2. 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.
3. If the first test condition turns out false, then it is compared with the second condition.
4. 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

• Decision making or branching statements are used to select one path based on the result of the evaluated expression.
• 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.