Loop Exercises
Write a C program to input a number from user and find reverse of the given number using for loop. How to find reverse of any number using loop in C program. Logic to find reverse of a number in C programming.
Required knowledge
Basic C programming, While loop
Logic to find reverse of a number
Step by step descriptive logic to find reverse of a number.
- Input a number from user to find reverse. Store it in some variable say num.
- Declare and initialize another variable to store reverse of num, say reverse = 0.
- Extract last digit of the given number by performing modulo division. Store the last digit to some variable say lastDigit = num % 10.
- Increase the place value of reverse by one. To increase place value multiply reverse variable by 10 i.e. reverse = reverse * 10.
- Add lastDigit to reverse i.e. reverse = reverse + lastDigit.
- Since last digit of num is processed hence, remove last digit of num. To remove last digit divide num by 10 i.e. num = num / 10.
- Repeat step 3 to 6 till num is not equal to (or greater than) zero.
Let us implement the above logic in C program.
Program to find reverse of a number
/** * C program to find reverse of a number */ #include <stdio.h> int main() { int num, reverse = 0; /* Input a number from user */ printf("Enter any number to find reverse: "); scanf("%d", &num); /* Repeat the till 'num' becomes 0 */ while(num != 0) { /* * Increase place value of reverse and * add last digit to reverse */ reverse = (reverse * 10) + (num % 10); /* Remove last digit from 'num' */ num /= 10; } printf("Reverse = %d", reverse); return 0; }
Output
Enter any number to find reverse:3136
Reverse =6313