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Write a Java Program to Check Whether a Number is Prime or Not
PROGRAM: Java Program to Check Whether a Number is Prime or Not
/* Java Program to Check Whether a Number is Prime or Not */
1: Program to Check Prime Number using a for loop
public class Main {
public static void main(String[] args) {
int num = 29;
boolean flag = false;
// 0 and 1 are not prime numbers
if (num == 0 || num == 1) {
flag = true;
}
for (int i = 2; i <= num / 2; ++i) {
// condition for nonprime number
if (num % i == 0) {
flag = true;
break;
}
}
if (!flag)
System.out.println(num + ” is a prime number.”);
else
System.out.println(num + ” is not a prime number.”);
}
}
2: Program to Check Prime Number using a while loop
public class Main {
public static void main(String[] args) {
int num = 33, i = 2;
boolean flag = false;
// 0 and 1 are not prime numbers
if (num == 0 || num == 1) {
flag = true;
}
while (i <= num / 2) {
// condition for nonprime number
if (num % i == 0) {
flag = true;
break;
}
++i;
}
if (!flag)
System.out.println(num + ” is a prime number.”);
else
System.out.println(num + ” is not a prime number.”);
}
}
