显示从 1 到 N 的所有质数的 Java 程序
原文:https://www . geesforgeks . org/Java-program-to-display-all-prime-numbers-from-1-n/
对于给定的数 N，目的是找出从 1 到 N 的所有素数。
示例:
Input: N = 11
Output: 2, 3, 5, 7, 11
Input: N = 7
Output: 2, 3, 5, 7
方法 1:
- 首先，考虑给定的数字 N 作为输入。
- 然后应用 for 循环来迭代从 1 到 n 的数字
- 最后，检查每个数字是否是质数，如果是质数，然后用暴力打印。
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find all the
// prime numbers from 1 to N
class gfg {
// Function to print all the
// prime numbers till N
static void prime_N(int N)
{
// Declaring the variables
int x, y, flg;
// Printing display message
System.out.println(
"All the Prime numbers within 1 and " + N
+ " are:");
// Using for loop for traversing all
// the numbers from 1 to N
for (x = 1; x <= N; x++) {
// Omit 0 and 1 as they are
// neither prime nor composite
if (x == 1 || x == 0)
continue;
// Using flag variable to check
// if x is prime or not
flg = 1;
for (y = 2; y <= x / 2; ++y) {
if (x % y == 0) {
flg = 0;
break;
}
}
// If flag is 1 then x is prime but
// if flag is 0 then x is not prime
if (flg == 1)
System.out.print(x + " ");
}
}
// The Driver code
public static void main(String[] args)
{
int N = 45;
prime_N(N);
}
}
Output
All the Prime numbers within 1 and 45 are:
2 3 5 7 11 13 17 19 23 29 31 37 41 43
时间复杂度: O(N 2 )
方法 2:
- 首先，考虑给定的数字 N 作为输入。
- 然后应用 for 循环来迭代从 1 到 n 的数字
- 最后，检查每个数字是否是质数，如果是质数，用平方根法打印出来。
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find all the
// prime numbers from 1 to N
class gfg {
// Function to print all the
// prime numbers till N
static void prime_N(int N)
{
// Declaring the variables
int x, y, flg;
// Printing display message
System.out.println(
"All the Prime numbers within 1 and " + N
+ " are:");
// Using for loop for traversing all
// the numbers from 1 to N
for (x = 2; x <= N; x++) {
// Using flag variable to check
// if x is prime or not
flg = 1;
for (y = 2; y * y <= x; y++) {
if (x % y == 0) {
flg = 0;
break;
}
}
// If flag is 1 then x is prime but
// if flag is 0 then x is not prime
if (flg == 1)
System.out.print(x + " ");
}
}
// The Driver code
public static void main(String[] args)
{
int N = 45;
prime_N(N);
}
}
Output
All the Prime numbers within 1 and 45 are:
2 3 5 7 11 13 17 19 23 29 31 37 41 43
版权属于：月萌API www.moonapi.com，转载请注明出处
