**6.29(双素数)双素数是指一对差值为2的素数。例如:3和5就是一对双素数,5和7是一对双素数,而11和13也是一对双素数。编写程序,找出小于1000的所有双素数。如下所示显示结果: (3,5) (5,7) … **6.29(Twin primes)(Twin primes) Twin primes are a pair of prime numbers that differ by 2. For example, 3 and 5 are twin primes, 5 and 7 are twin primes, and 11 and 13 are twin primes. Write a program to find all twin primes less than 1,200. Display the output as follows: (3,5) (5,7) …
参考代码:
package chapter06;publicclassCode_29{
publicstaticvoidmain(String[] args){
for(int i =3;i +2<1000;i++)if(isPrime(i)&&isPrime(i+2))
System.out.printf("(%d, %d)\n", i, i+2);}publicstaticbooleanisPrime(int number){
for(int i =2;i <= Math.sqrt(number);i++)if(number % i ==0)returnfalse;returntrue;}}
结果显示:
(3,5)(5,7)(11,13)(17,19)(29,31)(41,43)(59,61)(71,73)(101,103)(107,109)(137,139)(149,151)(179,181)(191,193)(197,199)(227,229)(239,241)(269,271)(281,283)(311,313)(347,349)(419,421)(431,433)(461,463)(521,523)(569,571)(599,601)(617,619)(641,643)(659,661)(809,811)(821,823)(827,829)(857,859)(881,883)
Process finished with exit code 0