The if statement in C programming language is used to execute a block of code only if condition is true.
Syntax of If Statement
if(condition_expression) {
/* code to be execute if the condition_expression is true */
statements;
}
/* code to be execute if the condition_expression is true */
statements;
}
The if statement checks whether condition_expression is true or false. If the condition_expression is true, then the block of code inside the if statement is executed but if condition_expression is false, then the block of code inside the if statement is ignored and the next statement after if block is executed.

C Program to print Pass or Failed using If Condition Statement
#include <stdio.h> int main(){ int marks; printf("Enter your Marks : "); scanf("%d", &marks); /* Using if statement to decide whether a student failed in examination or not*/ if(marks < 40){ printf("You Failed :(\n"); } if(marks >= 40){ printf("Congrats You Passed :)\n"); } return(0); }Above program check whether a student passed or failed in examination using if statement.
Output
Enter your Marks : 70 Congrats You Passed :)
Enter your Marks : 35 You Failed :(
Points to Remember about If Statement
- The condition_expression is a boolean expression. It must evaluate to true or false value(In C, all non-zero and non-null values are considered as true and zero and null value is considered as false).
- We may use more than one condition inside if statement
For Example:
if(condition_one && condition_two) {
/* if code block */
} - Opening and Closing Braces are optional, If the block of code of if statement contains only one statement
For Example:
if(condition_expression)
statement1;
statement2;
In above example only statement1 will gets executed if condition_expression is true.