java求素数
package code;
/**
*
* @author Smart
*
*/
public class Prame {
/**
* @param args the command line arguments
*/
public static void main(String[] args)
{
int a,b;
a=0;
b=0;
for (int i = 101; i <= 200; i++) {
for(int j = 2; j < i; j++) {
if( i%j == 0 )
a++;
}
if ( a < 1 ) {
b++;
System.out.println(i);
a = 0;
} else
a = 0;
}
// TODO code application logic here
System.out.println("101至200之间有" + b + "个素数");
}
}
优化后的程序
package code;
/**
*
* @author Smart
*
*/
public class PrameB {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
int count = 0;
for (int i = 101; i < 200; i += 2) {
boolean b = false;
for(int j=2; j <= Math.sqrt(i); j++) {
if(i % j == 0) {
b = false; break;
} else
b = true;
}
if(b == true) {
count ++;System.out.println(i );
}
}
System.out.println( "素数个数是: " + count);
}
}