Program using While Loop

Unlike most of the computer programming languages, a while loop is a control flow statement that allows code to be executed repeatedly based on a given boolean condition in C or C++. The while loop can be thought of as a repeating if statement. Here is some program using while Loop:

C Program to return reverse of a three digit number:

Assume that you have input a number 123 to computer and computer return it to 321. we know that if a number divided by 10 then its reminder is always the last digit of inputted number. (123%10 =3, 12%10=2)

 #include<stdio.h>
void main()
{
    int number,reverse=0,reminder;
    clrscr();
    printf("Enter any three digits value: ");
    scanf("%d",&number);
    while(number>0)
    {
         reminder=number%10;
         reverse=(reverse*10)+reminder;
         number=number/10;
    }
    printf("Reverse value is %d",reverse);

}

Output:

C Program to find Armstrong number between a range :

An Armstrong number is the sum of the cubes of its digits and is equal to the number itself. For example, 371 is an Armstrong number since 3**3 + 7**3 + 1**3 = 371.

 #include<stdio.h>
void main()
{
 int i=0,number, reminder, armstrong=0,term;
 clrscr();
 printf("Enter term to search Armstrong:");
 scanf("%d", &term);
 while(i<=term)
 {
 number=i;
 while(number>0)
 {
 reminder=number%10;
 armstrong =armstrong +(reminder*reminder*reminder);
 number=number/10;
 }
 if(armstrong ==i)
 printf("Armstrong No is %d",i)

 i++;
 }
}

Output:

C Program to check a given number whether palindrome or not.

A palindrome is a word, phrase, number, or other sequences of characters which read the same backwards or forward. Allowances may be made for adjustments to capital letters, punctuation, and word dividers. Examples in English include “A man, a plan, a canal, Panama!”, “Amor, Roma”, “race car”, “stack cats”, “step on no pets”, “taco cat”, “put it up”, “Was it a car or a cat I saw?” and “No ‘x’ in Nixon” ,”121″ etc.

In case of number we use reverse method:

 #include<stdio.h>
void main()
{
   int num,value,reminder,tmp;
   printf("Enter any number to check palindrome");
   scanf("%d",&num);
   tmp=num;
   while(tmp>0)
   {
      reminder=tmp%10;
      value=value*10+reminder;
      tmp=tmp/10;

   }
   if (num==value)
   {
     printf("Entered Number %d is a palidrome number",num);
   }
   else
   {
     printf("Entered Number %d is not apalindrome number",num);
   }
}

In case of String we use string function substr()

 #include<stdio.h>
#include<string.h>
void main()
{
 char word[100],rev[100];
 clrscr();
 printf("Enter any word: ");
 scanf("%s", &word);
 strcpy(rev,word);
 if (strcmp(word,strrev(rev))==0)
 {
 printf("The word is palindrome");
 }
 else
 {
 printf("The word is not a palindrome");
 }
 getch();

}