C Program To Reverse a Number

In this post, we will know how to reverse a number Using C Programming language.

Reversing a number means interchanging of the digits through which the first digit of the number becomes the last digit and vice versa. For example: 18 after reverse becomes 81. 

So, without further ado, let’s begin the tutorial.

C Program To Reverse a Number

// C Program To Reverse a Number
int main(){
    int n, num = 0, remainder;
    
    // Asking for Input
    printf("Enter an integer: ");
    scanf("%d", &n);
    
    // logic
    while (n != 0){
        remainder = n % 10;
        num = num * 10 + remainder; 
        n = n / 10;
    }
    printf("Reversed Number is %d.", num);
    return 0;
}

Output

Enter an integer: 1234
Reversed Number is 4321.

How Does This Program Work ?

    int n, num = 0, remainder;

In this program, we have declared three int data type programs named as n, num and remainder.

    // Asking for Input
    printf("Enter an integer: ");
    scanf("%d", &n);

Then, the user is asked to enter the number. This number will get stored in n named variable.

    // logic
    while (n != 0){
        remainder = n % 10;
        num = num * 10 + remainder; 
        n = n / 10;
    }

Now, while loop is used until n != 0 is false.

Inside the loop, the reverse number is computed using:
num = num * 10 + remainder

    printf("Reversed Number is %d.", num);

Finally, the reversed number which has been stored in the num variable is displayed as output using printf() function.

Some of the used terms are as follow:

#include <stdio.h> – In the first line we have used #include, it is a preprocessor command that tells the compiler to include the contents of the stdio.h(standard input and output) file in the program. 

The stdio.h is a file which contains input and output functions like scanf() and printf() to take input and display output respectively. 

Int main() – Here main() is the function name and int is the return type of this function. The Execution of any Programming written in C language begins with main() function. 

scanf() – scanf() function is used to take input from the user.  

printf() – printf() function is used to display and print the string under the quotation to the screen.  

while Loop – In the while loop, the statements inside the body of the while loop keeps executing until it is evaluated to False.

% – It is known as Modulus Operator and provides remainder after division.

// – Used for Commenting in C. 

Conclusion

I hope after going through this post, you understand how to reverse a number using C Programming language.

If you have any doubt regarding the topic, feel free to contact us in the Comment Section. We will be delighted to help you.