For loop output primes Explore "Java"

One, Judge 953 is not a prime number (prime number).

Code:

1  /**2 Judge 953 is not a prime number (prime number)3 Analysis:4 primes are integers in a natural number greater than 1, which cannot be divisible by other natural numbers except 1 and the integer itself. 5 Assuming that 953 is a prime number, then:6 953% 2!== 07 953% 3!== 08 953% 4!== 09 ...Ten 953% 952!== 0 One The inverse is that 953 is not a prime number, as long as 953 is divisible by any integer between 2~952.  A  - The divisor is incremented from 2 to 952, followed by integers, and is represented by A for loop: - for (int i=2;i<953;i++) { the Judging whether 953 can be I integer - if it can be divisible, then 953 is not prime, end the loop, jump out of the output "953 is not prime" - if it cannot be divisible, then 953 is the prime, ending the loop, jumping out of the output "953 is prime" -             } +  */ -   +   Public classIsPrime A { at      Public Static voidMain (string[] args) { -  -         intnum = 953; -         BooleanIsPrime =true;//mark number num By default is prime -          for(inti=2;i<num;i++) { -             if(num%i==0) {//num can be 2~num-1 between the natural number of integers inIsPrime =false;//Mark number num as non-prime -                  Break;//End Loop to             } +         } -  theSystem.out.println (isprime?num+ "is prime": num+ "is not prime");  *  $     }Panax Notoginseng}

The Code results show:

Ii. List of all primes between 1~100

Code:

1 /**2 List all primes between 1~1003 Analysis:4 The code snippet above indicates whether the natural number of Num 953 is a prime,5 assuming that NUM is 937, it is judged that 937 is not a prime number,6 assuming that num is 933, it is judged that 933 is not a prime number,7 8 Therefore, NUM is set to a variable that is incremented from 1~100 with a for loop,9 Place the code snippet of the door into the for loop and print it as a prime number. Ten  One for (int num=2;num<=100;num++) { A  - code snippet to determine if Num is a prime number -  the         } -  - */ -  +  Public classIsPrime - { +      Public Static voidMain (string[] args) { A  at          for(intnum=2;num<=100;num++) { -             BooleanIsPrime =true;//mark number num By default is prime -              for(inti=2;i<num;i++) { -                 if(num%i==0) { -IsPrime =false; -                      Break; in                 } -             } to             if(isprime) { +System.out.print (num+ ""); -             } the         } *     } $}

Description of code Explanation:

The Code results show:

List all primes between 1~100, and display 5 numbers per line.

Code:

1 /**2 lists all the primes between 1~100, and displays 5 numbers per row. 3 Analysis:4 you can get all the prime numbers between 1~100 from the previous example code. 5 To show 5 numbers per row, you know that every time a prime number is drawn, you know that it is the first occurrence, and then you accumulate6 when the number is accumulated to 5 o'clock, the line is changed. 7 8 Therefore, a tag is required to record the number of times the output of each prime. 9 Ten */ One  A  Public classIsPrime - { -      Public Static voidMain (string[] args) { the          -         intCount = 0;//A counter that is used to record the number of times each prime is printed.  -          for(intnum=2;num<=100;num++) { -             BooleanIsPrime =true;//mark number num By default is prime +              for(inti=2;i<num;i++) { -                 if(num%i==0) { +IsPrime =false; A                      Break; at                 } -             } -             if(isprime) { -System.out.print (num+ ""); -count++;//record once for each prime number printed -                 if(count%5==0) {//each counter is recorded 5 times, and the line is changed once.  in System.out.println (); -                 } to             } +         } -     } the}

Code distortion: If the counter is implemented every 5 times, then the 0 can also achieve the corresponding count effect. Replace the above 25 lines of ~31 line code with the following code:

1 if (isprime) {2 System.out.print (num+ ""); 3 // record once for each prime number printed 4 if // The counter accumulates to the number 5 o'clock, and the line is changed one time. 5 System.out.println (); 6 // counter is placed 0 7     }8 } 　　 　　　　　

The Code results show:

Iv. Output 9*9 Multiplication table

Code:

1 /**2 output display 9*9 multiplication table3 1*1=14 1*2=2 2*2=25 1*3=3 2*3=6 3*3=96 1*4=4 2*4=8 3*4=12 4*4=167 ...8 1*9=9 2*9=18 ... and so on.  9*9=819 Ten Analysis: Follow the rules of each row and column One -The table is 9 rows in total, A -Several equations are required for each output of the first few lines -  - identity format is i*j=c the • Each line I increments from 1 to J, indicating that each J-row output can output a total of I equation - so using a for loop is represented as: - for (int i=1;i<=j;j++) { - ... +                 } - • Indicates line J + for (int j=1;i<=9;j++) { A Output Line//The loop body executes once, and then wraps once.  at                 } - so the first for loop body needs to be within the second for loop body.  - */ -  -  Public classTest03 - { in      Public Static voidMain (string[] args) { -          for(intj=1;j<=9;j++) { to              for(inti=1;i<=j;i++){ +System.out.print (i+ "*" +j+ "=" +i*j+ "");//i from 1~j cycle show, line J need to display 1~j identities -             } theSystem.out.println ();//each of the above I loop body performs an end, that is, the line is displayed, the line is changed once *         } $     }Panax Notoginseng}

The Code results show:

For loop output primes Explore "Java"