C Programming
- Print integer
- Add & subtract
- Odd & even
- Multiply & divide
- Check vowels
- Letter grade program
- Leap year program
- Sum of digits
- Prime numbers
- Sum of numbers
- Find factorial
- Fibonacci series
- Fibonacci triangle
- Number triangle
- Alphabet triangle
- Armstrong numbers
- Palindrome numbers
- Swap number
- Reverse number
- Decimal to binary
- Assembly code in C
- Matrix multiplication
- HCF & LCM
- nCr & nPr
- Print pattern
- Floyd’s triangle
- Pascal triangle
- Count digits
- Strong numbers
- Perfect numbers
- Sum of natural number
- Binary to decimal
- Decimal to octal
- Octal to decimal
- Binary to octal
- Octal to binary
- Add using pointer
- Bubble sort
- Insertion sort
- Selection sort
- Quick sort
- Binary search
- Linear search
- Largest element of array
- Smallest element of array
- Reverse Array
- Variable size & limit
- ASCII value of character
- Sum of array elements
- Number of element in array
- Merge two array
- Insert element in array
- Delete element from array
- Add two matrix
- Transpose matrix
- Print string
- Reverse string
- Delete vowels
- Sort string
- Remove spaces
- Swap string
- Random numbers
- Print date & time
- Print IP address
- Shut down computer
C program to reverse a number
In this C program to reverse number article we will make some program which will take integer as the input from user and print the reverse of that number. If a user gives the integer 123 then the program will print the output as 321. We can do such program in several way. Let’s see some example program of reverse a number using C.
Reverse number program
// reverse number program in C
#include<stdio.h>
int main(){
int num, rem, revNum = 0;
printf("Enter an integer to reverse it : ");
scanf("%d", &num);
while(num != 0){
rem = num % 10;
revNum = (revNum * 10) + rem;
num /= 10;
}
printf("\nReversed number is = %d\n",revNum);
return 0;
}
Output of this reverse number program:

Reverse number program using recursion in C
// reverse number program using recursion in C
#include <stdio.h>
long revNum(long num){ // function to reverse number
static long rem = 0;
if (num == 0){
return 0;
}
rem = rem * 10;
rem = (num % 10) + rem;
revNum(num / 10);
return rem;
}
int main(){
long number, reminder;
printf("Enter the number : ");
scanf("%ld", &number);
reminder = revNum(number);
printf("\nReverse number is = %ld\n", reminder);
return 0;
}
See output of reverse number program:

Previous page: Swap number
Next page: Decimal to binary