To check some given condition and perform some operations depending on the condition, there we need to use if statement. The syntax of if statement is:
if(expression){
//code to be executed
}
Flowchart of if statement in C:
Let’s see an example of if statement.
#include<stdio.h>
int main(){
int number=0;
printf("Enter a number:");
scanf("%d",&number);
if(number%2==0){
printf("%d is even number",number);
}
return 0;
}
After executing the code, our output looks like
Enter a number:4
4 is even number
Find the largest number of the three in C.
#include <stdio.h>
int main()
{
int a, b, c;
printf("Enter three numbers?");
scanf("%d %d %d",&a,&b,&c);
if(a>b && a>c)
{
printf("%d is largest",a);
}
if(b>a && b > c)
{
printf("%d is largest",b);
}
if(c>a && c>b)
{
printf("%d is largest",c);
}
if(a == b && a == c)
{
printf("All are equal");
}
}
After executing the code, our output looks like
Enter three numbers?
12 23 34
34 is largest
If-else Statement in C
To perform two operations for a single condition, we need to use if-else statement. Here one is for correctness of that condition, & other is for the incorrectness of the condition. If and else block cannot be executed simultaneously.
Syntax:
if(expression){
//code to be executed if condition is true
}else{
//code to be executed if condition is false
}
Flowchart of the if-else statement
Following example check whether a number is even or odd using if-else statement
#include<stdio.h>
int main(){
int number=0;
printf("enter a number:");
scanf("%d",&number);
if(number%2==0){
printf("%d is even number",number);
}
else{
printf("%d is odd number",number);
}
return 0;
}
After executing the code, our output looks like
enter a number:4
4 is even number
enter a number:5
5 is odd number
Flowing Program check whether a person is eligible to vote or not
#include <stdio.h>
int main()
{
int age;
printf("Enter your age?");
scanf("%d",&age);
if(age>=18)
{
printf("You are eligible to vote...");
}
else
{
printf("Sorry ... you can't vote");
}
}
After executing the code, our output looks like
Enter your age?18
You are eligible to vote...
Enter your age?13
Sorry ... you can't vote
If else-if ladder Statement
It is an extension of if-else statement, which is used to perform multiple cases for different conditions.
Flowchart of else-if ladder
#include<stdio.h>
int main(){
int number=0;
printf("enter a number:");
scanf("%d",&number);
if(number==10){
printf("number is equals to 10");
}
else if(number==50){
printf("number is equal to 50");
}
else if(number==100){
printf("number is equal to 100");
}
else{
printf("number is not equal to 10, 50 or 100");
}
return 0;
}
After executing the code, our output looks like
enter a number:4
number is not equal to 10, 50 or 100
enter a number:50
number is equal to 50
Following Program is calculating the grade of the student according to the specified marks
#include <stdio.h>
int main()
{
int marks;
printf("Enter your marks?");
scanf("%d",&marks);
if(marks > 85 && marks <= 100)
{
printf("Congrats ! you scored grade A ...");
}
else if (marks > 60 && marks <= 85)
{
printf("You scored grade B + ...");
}
else if (marks > 40 && marks <= 60)
{
printf("You scored grade B ...");
}
else if (marks > 30 && marks <= 40)
{
printf("You scored grade C ...");
}
else
{
printf("Sorry you are fail ...");
}
}
After executing the code, our output looks like
Enter your marks?10
Sorry you are fail ...
Enter your marks?40
You scored grade C ...
Enter your marks?90
Congrats ! you scored grade A ...