C program to print prime numbers from 1 to 100

prime numbers:

prime numbers are divisible by only 1 and that number itself. Eg.in this program, as per divisions, integer number 5 can be divided by 1 and integer number 5 which is nothing but original number so it is prime number. 2 is the only even prime number.
prime number:2,3,5,7,11,13,17,19,23,29,…

logic:

Below program to find prime number takes user input and then if condition inside for loop checks whether number is divisible by smaller number than input number which is 1 or number itself.

#include<stdio.h>
#include<conio.h>
#include<math.h>
void printprimes();
int checkprimes(int num);
void main()
{
  int i;
  int flag;
  printf("\n Prime numbers from 1 to 100:");
  printprimes();
  getch(); 
}  
void printprimes()
{
  int i,j;
  for(i=2;i<=100;i++)
  {
    if(checkprimes(i));
    printf("%d\t",i);
  }
} 
int checkprimes(int num)
{
  int j;
  for(j=2;j<=sqrt(num);j++)
  {
    if(num%j==0)
    return 0;
  } 
  return 1; 
}

Ouput:


programoutputSimilar programs:
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Program to find prime number using function

C program to check whether given number is palindrome or not using for loop

Define Palindrome number:

Palindrome number is viewed with same value after we do reversal of its digits.
Example: Say number is, number = 212, then reversal of its digits will make output be like number = 212. so that here 212 is a palindrome.

#include
#include
int palindrome(int val); 
int rever=0,remain=0; 
void main()
{
  int val;
  printf("\n Enter a number: ");
  scanf("%d",&val);
  if(val==palindrome(val))
  { 
    printf("\n %d is a palindrome",val);
  }
  else
  {
    printf("\n %d is not a palindrome",val); 
  } 
  getch();
}
int palindrome(int val)
{
  for(;val>0;val=val/10)
  {
    remain=val%10;
    rever=rever*10+remain;
  }
  return rever;
}

Ouput:

Enter a number: 212
212 is a palindrome

C program to check whether given number is palindrome or not using do while loop

Palindrome number:

It is an integer number that stays same after reversal of its digits.
Example: say value of integer is, N = 121, then output will be 121. So that value 121 is called palindrome.

#include
#include
int palindrome(int val); 
int rever=0,remain=0; 
void main()
{
  int num;
  printf("\n Enter a number: ");
  scanf("%d",&val);
  if(val==palindrome(val))
  { 
    printf("\n %d is a palindrome",val);
  }
  else
  {
    printf("\n %d is not a palindrome",val); 
  } 
  getch();
}
int palindrome(int val)
{
  do
  {
    remain=val%10;
    rever=rever*10+remain;
    val=val/10;
  }while(val>0);
  return rever;
}

Ouput:

Enter a number: 12121
12121 is a palindrome

c program to check whether a number is palindrome or not using while loop

Palindrome number is:

It is an integer that has same value even after the reversal of its digits.
Example: say the input, Number = 12121, after reversal is done,then Number = 12121. So that 12121 is called palindrome.

#include
#include
int palindrome(int val); 
int rever=0,remain=0; 
void main()
{
  int num;
  printf("\nEnter a number: ");
  scanf("\n%d",&val);
  if(val==palindrome(val))
  { 
    printf("\n%d is a palindrome no",val);
  }
  else
  {
    printf("\n%d is not a palindrome no",val); 
  } 
  getch();
}
int palindrome(int val)
{
  while(val)
  {
    remain=val%10;
    rever=rever*10+remain;
    val=val/10;
  }
  return rever;
}

Ouput:

Enter a number: 12321
12321 is a palindrome no

c program to reverse a number using for loop

Program

C Program to reverse digits of a number using for loop

#include
#include
void main()
{
  int val;
  int rever=0, remain=0;
  printf("\n Enter a number: ");
  scanf("%d",&val);
  for(;val>0;val=val/10)
  {
    remain = val%10;
    rever = rever*10+remain;
  }

  printf("\n reverse of number is = %d",rever); 
  getch();
}  

Output

Enter a number: 132
reverse of number is = 231

 

c program to reverse a number using do while loop

Program

Program in C for reversal of digits of a number using do while loop

#include
#include
void main()
{
  int val;
  int rever=0, remain=0;
  printf("\nEnter a number: ");
  scanf("\n%d",&val);
  do
  {
    remain = val%10;
    rever = rever*10+remain;
    val = val/10;
}while(val>0);

printf("\nreverse of the number = %d",rever);
getch();
}

Output

Enter a number: 254
reverse of the number = 452

c program to reverse a number using while loop

Program

Program to reverse digits of a number using while loop in c

#include<stdio.h>
#include<conio.h>
void main()
{
  int num;
  int rev=0, rem=0;
  printf("n Enter a number: ");
  scanf("%d",&num);
  while(num>0)
  {
    rem = num%10;
    rev = rev*10+rem;
    num = num/10;
  }
  printf("n reverse number = %d",rev);
  getch();
} 

Output

Enter a number: 123
Reverse number = 321

c program to check whether given number is armstrong number or not using for loop

#include<stdio.h>
#include<conio.h>
void main()
{
  int num, n, rem;
  int cube=0, sum=0;
  printf("n Enter a number: ");
  scanf("%d",&num);
  n = num;
  for(;n>0;n=n/10)
  {
    rem = n%10;
    cube = rem*rem*rem;
    sum = sum + cube;
  }
  if(num==sum)
  {
    printf("n %d is armstrong number",num);
  }
  else
  {
    printf("n %d not armstrong number",num);
  }
  getch();
}

Ouput:

Enter a number: 407
407 is armstrong number

 

C program to find and print armstrong numbers between 1 and 1000

Armstrong numbers:

Input : 153.
Calculating armstrong number: 153 =(1*1*1)+(5*5*5)+(3*3*3)= 1+125+27 =153 

If input equals output, 153==153, 153 is armstrong number.

#include<stdio.h>
#include<conio.h>
void main()
{
  int num, n, rem;
  int cube=0, sum; 
  printf("n Armstrong numbers between 1 and 1000 are: n");
  for(num=1;num<=1000;num++)
  {
    sum=0;
    n=num;
    while(n>0)
    {
      rem=n%10;
      cube=rem*rem*rem;
      sum=sum+cube;
      n=n/10;
    }
    if(num==sum)
    {
      printf("n%d is armstrong number",num);    
    }
  getch();
}

Ouput:

Armstrong numbers between 1 and 1000 are:
1 is armstrong number
153 is armstrong number
370 is armstrong number
371 is armstrong number
407 is armstrong number

 

c program to find and print all armstrong number between 1 to 500

Armstrong numbers are:

Input :say value is 370.
When doing calculation for armstrong number:
370 is equal to (3*3*3)+(7*7*7)+(0*0*0) so output is 27+343+0 = 370
If input value is similar with output which is 370==370, then 370 is called an armstrong no.

#include
#include
void main()
{
  int number, j, remain;
  int cube=0, sum; 
  printf("\n Armstrong numbers between the limit from 1 to 500 are: \n"); 
  for(number=0;number<=999;number++)   
  {     
  	sum=0;
	j=number;     
	while(j>0)
    {
      remain=j%10;
      cube=remain*remain*remain;
      sum=sum+cube;
      j=j/10; 
    }
     if(number==sum)
     printf("\n%d is an armstrong no.",number);    
  }
     getch();
}

Ouput:

Armstrong numbers between the limit from 1 to 500 are:
1 is an armstrong no.
153 is an armstrong no.
370 is an armstrong no.
371 is an armstrong no.
407 is an armstrong no.
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