JAVA exercises to find prime numbers

 PackageCom.zhang.hello; Public classTask {/*** 1. Output print 99 multiplication table **/     Public voidNO1 () { for(inti=1;i<10;i++){             for(intj=1;j<=i;j++) {System.out.print (J+ "*" +i+ "=" + (i*j) + "\ T");        } System.out.println (); }    }    /*** 2. Seek the sum of 1!+2!+3!+...+20!. *      * */     Public LongNO2 (LongN) {//n=20        LongS=0;  for(Longi=1;i<=n;i++){            LongK=1;  for(Longj=i;j>0;j--) {k*=J; } s+=K; }        returns; }    /*** 3. Seek the sum of 1!+5!+9!+...+21!. * */     Public DoubleNO3 (DoubleN) {//n=21        DoubleS=0;  for(intI=1;i<=n;i+=4){            DoubleK=1;  for(intj=i;j>0;j--) {k*=J; } s+=K; }        returns; }    /*** 4. Seek 1+ (1+2) + (1+2+3) + + (1+2+3+     +10) of the value? * */     Public intNO4 (intN) {//n=10        intS=0;  for(inti=1;i<=n;i++){            intK=0;  for(intj=i;j>0;j--) {k+=J; } s+=K; }        returns; }    /*** 5. Output Yang Hui triangle **/     Public voidNO5 () {intH=1;  for(inti=0;i<4;i++){             for(intj=4;j>i;j--) {System.out.print (" "); }                         for(intj=0;j) {System.out.print ("@"); } h+=2; System.out.println (""); } System.out.println ("-------------"); H=1;  for(inti=0;i<4;i++){             for(intj=4;j>i;j--) {System.out.print (" "); }                         for(intj=0;j){                if(j%2==0) System.out.print ("@"); ElseSystem.out.print (""); } h+=2; System.out.println (""); }    }    /*** 6. Outputs all primes of 100 to 1000 bits 3 **/     Public voidNO6 () {Boolean[] Prime=New Boolean[1000];  for(inti=0;i<1000;i++){            if(i%2==0) prime[i]=false;//Exclude even numbers            Elseprime[i]=true; }                         for(intI=3;I&LT;=MATH.SQRT (i+=2);){            if(Prime[i]) {//If he is prime, his multiples are all ruled out                 for(intj=i+i;j<1000;j+=i) {Prime[j]=false; }            }        }                                 for(inti=0;i<1000;i++){            if(prime[i]&&i>99&&i<1000&&i%10==3) System.out.println (i+" "); }    }     Public Static voidMain (string[] args) {Task T=NewTask ();        T.no1 (); System.out.println (T.no2 (20)); System.out.println (T.NO3 (21.0)); System.out.println (T.no4 (10));        T.no5 ();            T.no6 (); }}

JAVA exercises to find prime numbers