C Program to Print All Prime Numbers between 1 to N

A Prime number is a natural number greater than 1 that is only divisible by either 1 or itself. All numbers other than prime numbers are known as composite numbers.

A prime number is a positive integer which is divisible only by 1 and itself. For example: 2, 3, 5, 7, 11, 13

Example: Program to Print Prime Number

#include<stdio.h>#include<conio.h> int main(){ int N, i, j, isPrime, n; printf("To print all prime numbers between 1 to N\n"); printf("Enter the value of N\n"); scanf("%d",&N); /* For every number between 2 to N, check whether it is prime number or not */

printf("Prime numbers between %d to %d\n", 1, N); for(i = 2; i <= N; i++){ isPrime = 0;

/* Check whether i is prime or not */

for(j = 2; j <= i/2; j++){

/* Check If any number between 2 to i/2 divides I completely If yes the i cannot be prime number */

if(i % j == 0){ isPrime = 1; break; } } if(isPrime==0 && N!= 1) printf("%d ",i); } getch(); return 0;}

Output

To print all prime numbers between 1 to N
Enter the value of N
50
Prime numbers between 1 to 50
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47

If the for loop terminates when the test expression of loop, the entered number is a prime number. The value of prime is equal to 0 in this case.

If the loop terminates because of break statement inside the if statement, the entered number is a nonprime number. The value of flag is 1 in this case.