Write a C program to reverse the number

In the C programming language, to reverse a number means to rearrange its digits so that the digit at the last position becomes the first, and vice versa. For example, the number 2543, its reverse would be 3452.

// Write a c program to reverse the number given by the user.
    #include<stdio.h>
    int main(){
        int n, reverse = 0;
        printf("Enter the number : ");
        scanf("%d", &n);
        while(n > 0){
            int last_digit = n % 10; // get the last digit from the number.
            reverse = (reverse * 10 ) + last_digit; // Store the last digits into the reverse integer variable.
            n /= 10; // remove the last digit from the number.
        }
        printf("Reverse : %d", reverse);
        return 0;
    }

#include<stdio.h>

This line includes the library of the input/output operation, After includes this line we can used the printf() function and scanf() function.

int main(){ 

It is the main function of the program, which is also called as the entry point of any c program. Which means every programs start from the main() function.

int n, reverse = 0;

Declared the variable as integers names n and reverse = 0.

printf("Enter the number : ");

It is show the prompts to the user enter the number using printf().

scanf("%d", &n);

Reads the number from the user as integers and store the value in n variable, "%d" is the format specifier which indicates that can only store the integer value.

// while loop to reverse the number
    while(n > 0){
        int last_digit = n % 10; 
        reverse = (reverse * 10 ) + last_digit;
        n /= 10;
    }

Use the while loop and the execute the statement inside the loop while n > 0. The lines into the loop works int last_digit = n % 10; get the last digit from the number. reverse = (reverse * 10 ) + last_digit; Store the last digits into the reverse integer variable.  n /= 10; remove the last digit from the number.

printf("Reverse : %d", reverse);

Displayed the reverse of the given  number using printf() function.

return 0;
    }

Successfully execute the program, and return 0..

Algorithm

1. START
2. DECLARED n, SET reverse = 0
3. DISPLAY Enter the number
4. READ number from user n
5. while (n > 0) true then GO TO Step 6, 7, 8, otherwise GO TO Step 9.
6. int last_digit = n % 10. Get the last digit.
7. reverse = (reverse * 10) + last_digit. Store the last digit into the reverse varialbe.
8. n /= 10; Remove the last digit from the n variable.
9. DISPLAY reverse number.
10. END

Pseudocode

// Pseudocode
    1. INCLUDE stdio.h
    2. FUNCTION main()
        1. DECLARE and SEt n, reverse = 0 as integer
        2. PRINT "Ente the number : "
        3. READ n FROM USER
        4. while (n > 0)
            1. SET last_digit = n % 10
            2. SET reverse = (reverse * 10) + last_digit
            3. SET n/=10 OR n = n / 1
        5. PRINT "Reverse : %d", reverse
        6. RETURN 0
    3. END