Prime Number Program in C using For loop

Prime Number Program in C using For loop

Prime number program to print from 1 to 100.

C program to print numbers from 1 to 100:

#include<stdio.h>

int main()
{

  int limit = 100;

    printf("Prime numbers between 1 and 100 are: ");
    for(int i = 2; i < limit; i++)
    { 
     int flag = 0;

     for(int j=2;j < i;j++)
      {

             if(i%j==0)
              {

                 flag = 1;

                 break;

             }

        }

         if(flag ==0)

             printf("%d ",i);

    }

   return 0;

}

Output:

Prime numbers between 1 and 100 are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.

Explanation of the above program: 

1. If the For loop condition (i <= limit) is true then loop enters into for loop and check the if condition (i%j == 0). 
2. If the condition is true the Entered number is not the prime number.
3.  If the condition is False, then the Prime number is printed up to the given limit. When for loop condition (101 <=100) then the program terminates.

Prime Number Program in C using For loop

Prime number program to print from 1 to N.

C program to print numbers from 1 to N:

#include<stdio.h>

int main(){

  int i,j,count,k;

    printf("Enter max range: ");

    scanf("%d",&k);

    for(i = 1;i<=k;i++)

     {

         count = 0;

         for(j=2;j<=i/2;j++){

             if(i%j==0){

                 count++;

                 break;

             }

        }

         if(count==0 && i!= 1)

             printf("%d ",i);

    }

   return 0;

}

Output:

Enter max range: 70

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67.

Explanation of the above program: 

1. First, the user should give the range value from the keyboard. the value is stored in the variable "k". 
2. If the For loop condition (i <= limit) is true then loop enters into for loop and check the if condition (i%j == 0). 
3. If the condition is true the Entered number is not the prime number.
4.  If the condition is False, then the Prime number is printed up to the given limit. When for loop condition (101 <=100) then the program terminates.

See also: Factorial Program in Java

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