[C language series] - print prime numbers between 100 and 200

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Introduction to this article ：C Language implementation 100~200 Print prime numbers between ！

Get to know the author ： Aspire to be a great programmer , Xiaobai, who is currently a sophomore in College .

Inspirational terms ： The tediousness of programming , Let's study together and become interesting ！

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List of articles

What is a prime number

Their thinking

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What is a prime number

For prime numbers, a number can be 1 And divide themselves , Besides, it cannot be divided by any number
such as ： take 13 For this number , Besides being 1 And myself 13 In addition to Division , It can't be divided by any number
Common prime numbers, such as ：1,2,3,5,7,11,13,17…

Their thinking

The method we use here is ： Trial division （ Use more than 2 To a number less than or equal to this number to modulus with this number , If the remainder is 0 It's not a prime , If it is not 0, Just print this number （ As a prime number ））

3. Directly start a code to see ：

#define _CRT_SECURE_NO_WARNINGS 1
// Print 100~200 The prime between 
#include<stdio.h>
int main()
{
    int i = 0;// So let's define one i, Prepare for the next cycle 
    for (i = 100; i <= 200; i++)// Define a for loop 
    {
        int j = 0;// Define a for use with 100-200 Divide the numbers between 
        for (j = 2; j <= i; j++)// Use more than 2, Less than i Of j modulus 
        {
            if (i % j == 0)// if i Can be j Divide and jump out of the loop 
            {
                break;
            }
        }
      if (j>=i)//j Keep looking for , Until greater than is found i The number of is not found to be divisible , Is a prime number 
        {
            printf("%d ", i);// Print out prime numbers 
        }  
    }
    return 0;
}

Finally, the result of running is ：

4. We all know that even numbers cannot be prime numbers, so we can further modify our code ： It was originally i++ Of , It can be changed to i+2 :

#include<stdio.h>
int main()
{
    int i = 0;// So let's define one i, Prepare for the next cycle 
    for (i = 101; i <= 200; i+=2)// Define a for loop 
    {
        int j = 0;// Define a for use with 100-200 Divide the numbers between 
        for (j = 2; j <= i; j++)// Use more than 2, Less than i Of j modulus 
        {
            if (i % j == 0)// if i Can be j Divide and jump out of the loop 
            {
                break;
            }
        }
      if (j>=i)//j Keep looking for , Until greater than is found i The number of is not found to be divisible , Is a prime number 
        {
            printf("%d ", i);// Print out prime numbers 
        }  
    }
    return 0;
}

The final result is the same as before ！

     （ Just a novice blogger , No, you can help point out , modify ）