If Statement in C

The If statement in C language is one of the most useful decision-making statements in real time programming. It allows the compiler to test the condition first and then, depending upon the result it will execute the statements. If the test condition is true then only statements with in the if statement is executed.

Syntax of If Statement in C

If statement in C language has simple structure:

// If statement in C Syntax
if (test condition)
{
 
  Statement 1;
  Statement 2;
  Statement 3;
  ………….
  ………….
  Statement n;
}

From the above code, If the test condition in the If statement is true, then the statements (Statement 1, Statement 2, Statement 3, ……., Statement n) will be executed, otherwise all these statements will be skipped. Let us see the flow chart for better understanding.

Example for If statement in C language

This program will check for the positive number using if statement

/* If Statement in C Programming Example */
#include <stdio.h>

int main()
{
 
 int number;
 
 printf("Enter any integer Value\n");
 scanf("%d",&number);
 
 if( number >= 1 )
 {
   printf("You Have Entered Positive Integer\n");
 }
  
 return 0;
}

NOTE: For the single printf statement curly brackets is not required but for multiple or group of statements it is mandatory. It is always good practice to use curly brackets following the If statements.

OUTPUT

ANALYSIS

If you look at the above if condition, Value stored in the number variable is greater than or equal to 0 that’s why it printed (print statement) inside the curly brackets ({}}.

From the above example, what happens if the condition fails? (number < 1).

It print nothing because we don’t have nothing to print after the if statement. Hope you are confused with the result, let us see the flow chart

Flow Chart for If Statement in C Language

The flow chart of a If in C programming is as shown below:

If the test condition is true then STATEMENT 1 is executed followed by STATEMENT N. If the condition is False then STATEMENT N is executed because it is out of the if condition block and it has nothing to do with the condition result.

/* If Statement in C Programming Example */
#include <stdio.h>

int main()
{
 int number;
 
 printf("Enter any integer Value\n");
 scanf("%d",&number);
 
 if( number >= 1 )
 {
   printf("You Have Entered Positive Integer\n");
 }
 
 printf("This Message is not coming from IF STATEMENT\n");
 
 return 0;
}

OUTPUT

You can observe from the above output, it printed both the printf statements because 22 is greater than 1. Let’s try the negative values to deliberately fail the condition

If condition failed here (number < 1). It print nothing from the If condition block so it printed only one printf statement which is outside the statement block.