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Ques:-21) – Write a program to check whether number entered through keyboard is palindrome or not.
Here’s a C program that checks whether a number entered through the keyboard is a palindrome or not:
#include"stdio.h"
#include"conio.h"
void main()
{
int num,revnum=0,num1,rem=0;
clrscr();
printf("enter any number:");
scanf("%d",&num);
num1=num;
for(num;num>0;num=num/10)
{
rem=num%10;
revnum=(revnum*10)+rem;
}
if(revnum==num1)
printf("\nnumber is palindrome");
else
printf("\nnumber is not palindrome");
getch();
Out Put
Enter any number: 12
number is not palindrome
Another Example
#include <stdio.h>
int main() {
int num, reversedNum = 0, remainder, originalNum;
// Prompt user to enter a number
printf("Enter an integer: ");
scanf("%d", &num);
// Store the original number
originalNum = num;
// Reverse the number
while (num != 0) {
remainder = num % 10;
reversedNum = reversedNum * 10 + remainder;
num /= 10;
}
// Check if the original number is equal to its reverse
if (originalNum == reversedNum) {
printf("%d is a palindrome.\n", originalNum);
} else {
printf("%d is not a palindrome.\n", originalNum);
}
return 0;
}
Explanation
Variables:
num: to store the number entered by the user.reversedNum: to store the reversed number.remainder: to store the remainder when calculating the reverse.originalNum: to store the original number for comparison.
Input:
- The program prompts the user to enter an integer.
- The entered number is read using
scanfand stored innum.
Reverse Calculation:
- The
whileloop runs untilnumbecomes 0. - In each iteration, the last digit of
numis obtained usingnum % 10and stored inremainder. reversedNumis updated by multiplying it by 10 and adding theremainder.numis divided by 10 to remove the last digit.
- The
Palindrome Check:
- After reversing, the program compares
originalNumwithreversedNum. - If they are equal, the number is a palindrome. Otherwise, it is not.
- After reversing, the program compares
Output:
- The result is printed based on the comparison.
Sample Output
Example 1: Palindrome Number
Enter an integer: 121
121 is a palindrome.
Example 2: Not a Palindrome Number
Enter an integer: 123
123 is not a palindrome.
This C program effectively checks if the entered number is a palindrome by reversing the digits and comparing the reversed number to the original.
