Judge the prime number between 2-

Before judging the prime numbers between 2-, we should first clearly understand the prime standard:

Prime Number: in a natural number greater than 1, apart from 1 and the integer itself, it cannot be divisible by other natural numbers.

1) Apart from 1 and itself, it cannot be divisible by other natural numbers;

2) 2 is a unique prime number that can be divisible by 2;

3) except for 2, all even numbers are numbers.

C # is implemented as follows:

// 2 is the minimum prime number Console. writeLine (2 + ""); // defines a count variable and calculates the number of prime numbers in 3-. int count = 0; // 2 is already a prime number, therefore, you only need to judge from 3 for (int I = 3; I <= 100; I ++) {// assign I to the variable xint x = I; // define an identity scalar and set the State bool flag to false; // determine whether x meets the condition for (int j = 2; j <x; j ++) {// can be divisible by 2 and any integer smaller than him. It is not a prime number if (x % j = 0) {// if it is not a prime number, flag is set to trueflag = true; // jump out of the loop and determine the next digit break;} if (flag = true) {continue;} // if the flag is false, else {// print the prime number Console. writeLine (x); count ++ ;}// count + 1 calculate all prime numbers in 2-, with a total of 25 consoles. writeLine (count + 1 );

650) this. width = 650; "src =" http://www.bkjia.com/uploads/allimg/131228/192633KN-0.gif "alt =" j_0057.gif "/> for beginners, this judgment is still difficult, but with learning, you will understand what is going on.

Come on !!!

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