Java Learning Notes (iv)-Looping statements

While loop

/* * While loop * loop variable, you can control the number of cycles. */ public  class  test{public  static  void  main  (string[] args) {int  count = 5 ; while         (Count > 0 ) {System.        out . println ( "Hello World"  + count--); } System.        out . println (count); System.    out . println (); }}

/* * While loop * Implement 1~100 's sum */ public  class  test{ Public  static  void  main     (string[] args) {//i represents a loop variable, at which I can not only control the number of cycles, I can also represent a specific value.         int  i = 1 ; int  sum = 0 ;        //for storing results  while         (I <= 100 ) {sum + = i;            //sum = sum + i;  i++;        //loop variable self-increment } System.    out . println (sum); }}

Do.. While loop

/ * * do. While loop * While loop difference? */ Public classtest{ Public Static void Main(string[] args) {//cyclic variable, mainly used for control loops.         intCount1 =0; Do{System. out. println ("Hello World"); } while(Count1 >0);//do. While loop to achieve the sum of 1~100        inti =1;intsum =0; Do{sum + = i;//sum = sum + i;i++; } while(I <= -); System. out. println (sum); }}

For loop

/ * * For loop */ Public classtest{ Public Static void Main(string[] args) { for(inti =0; I <5; i++) {System. out. println ("Hello World"); }/* * For statement implementation of 1~100 */        intsum =0; for(inti =1; I <= -;        i++) {sum + = i; } System. out. println (sum);//int i = 0;//For (SYSTEM.OUT.PRINTLN ("Expression 1"); i++ < 2; System.out.println ("Expression 3"))//      {//System.out.println ("loop Body");//      }}}

/ * * For attention points * / Public classtest{ Public Static void Main(string[] args) {//Expression 3 can have multiple statements         for(intx =0, y =Ten; X <5; x + +, y++) {}//For three expressions are optional        inti =1;intsum =0; for(; I <= -;)            {sum + = i;        i++; } System. out. println (sum);//second expression if not, indicates permanent true         for(;;) {System. out. println ("Hello World"); }    }}

Title: Print output 1~100 between the even and

/* Title: Print output 1~100 even between and */ Public classtest{ Public Static void Main(string[] args) {//while        intI1 =1;intSUM1 =0; while(I1 <= -)        {if(I1%2==0) {sum1 + = I1;        } i1++; } System. out. println (SUM1);//for        intsum2 =0; for(intI2 =1; I2 <= -; i2++) {if(I2%2==0) {sum2 + = i2; }} System. out. println (SUM2); }}

Title: All leap years in print output 1000-2050

/* Title: All leap years in print output 1000-2050 */ Public classtest{ Public Static void Main(string[] args) {//while        intYear = +; while(Year <=2050)        {if(Year%4==0&& Year% -!=0) || (Year% -==0)) {System. out. println (year);        } year++; }//for         for(inty = +; Y <=2050; y++) {if(Year%4==0&& Year% -!=0) || (Year% -==0)) {System. out. println (year); }        }    }}

Break statement

/ * * Break * in the loop, once the break statement is run, the loop is terminated. */ Public classtest{ Public Static void Main(string[] args) {//break         for(inti = -; i >0; i--) {ifI7==0) {System. out. println (i); Break; }        }intCount =Ten; while(true)        {if(Count%7==0)            { Break; } System. out. println (count--); } System. out. println ("for external code"); }}

Continue statements

/* * Continue * terminates this cycle and enters the next cycle. */ Public classtest{ Public Static void Main(string[] args) {inti =0; while(I++ <5)        {ifI3==0)            {Continue; } System. out. println (i); }//Through continue, realize the sum of even numbers between 1~100        intsum =0;intA =1; while(A <= -)        {ifA2!=0) {a++;Continue;            } sum + = A;        a++; } System. out. println (sum); }}

Nested loops

/ * Nested loops * / Public classtest{ Public Static void Main(string[] args) { for(Charc =' A '; C <=' D '; C + +) { for(inti =0; I <=3; i++) {System. out. print (C +""+ i +"\ T"); } System. out. println ();//Line break}    }}

Required, use * to print out a right triangle

/* * required, use * print out a right triangle * */ Public classtest{/*     *     **     ***     ****     *****     ******     *******     */     Public Static void Main(string[] args) {//print seven lines         for(introw =0; Row <7; row++) { for(intCol =0; Col <= Row; col++) {System. out. Print ("*"); } System. out. println (); }    }}

Print isosceles triangle

/* 5-row * 2*row-1 * * * * * * * * **************** * * Public classtest{ Public Static void Main(string[] args) { for(introw =1; Row <=5; row++) {//Print space             for(intSpa =1; Spa <=5-row; spa++) {System. out. Print (" "); }//print *             for(intCol =1; Col <= (2* Row-1); col++) {System. out. Print ("*"); } System. out. println (); }    }}

Java Learning Notes (iv)-Looping statements