(C language) 3 small Codes: 1+2+3+ · · +100=? And judge whether a year is a leap year or a normal year? And calculate the circumference and area of the circle?

We know , A program contains a small algorithm , Program is the implementation of Algorithm .

So in real life , We can use some code to implement some calculations , In terms of the ability of our primary procedural apes , We can implement small algorithms through programs , such as 1+2+3+······+100, We all know Gauss Algorithm ,（1+100）*50=5050, Now we can realize it by program , As shown below ：

#include<stdio.h>
int main()
{
	int i,n=0;
	for(i=0;i<=100;i++)
	{
		n+=i;
	}
	printf("1+2+3+···+100=%d",n);
 } 

The following is the operation interface ：

We can contact from junior high school C Programming , When others are still taking calculators , We have started to write our own computing programs in code , Isn't it very COOL, With the development of technology , We have more and more learning channels , Such as network , We can take courses from the best universities in the world , Through video teaching , We can listen to the lessons we want at home , Learn what we want to learn .

therefore , Now is a world of self-study , Find your own learning content , Improve yourself , meanwhile , We can appropriately improve our hands-on ability , For example, make some small furniture , Or write code , Or learn SCM , Or learn some skills , however , Now China is also developing , Improve the quality and diversity of Education , For example, primary school students have a lot of housework and other classes , All very good , We don't just read , Recite , Problem. , We also need to do real things .

And today's topic is 2 The first code is to judge the average year , Leap year , We all know , A year , If it can be 4 to be divisible by , At the same time, it cannot be 100 to be divisible by , So this year is leap year , If a year can be 400 to be divisible by , So this year is leap year , The rest of the years are normal , So how do we implement this algorithm ？

#include<stdio.h>                                       // The header file 
int main()                                              // Main function entry 
{                                                     
	int year;                                          // Define an integer variable  year
	printf(" Please enter a year ：");                         // Print out ： Please enter a year 
	scanf("%d",&year);                                 // Enter a year , such as 2030
	if((year%400 == 0)||(year%4==0&&year%100 !=0))     // Judge , Whether this year can be 400 to be divisible by , Or the concept can be 4 Divisible at the same time cannot be 100 to be divisible by 
		printf(" Leap year ");                                // If meet if Conditions , Print ： Leap year 
	else
		printf(" Ordinary year ");                                // If not satisfied if Conditions , Print ： Ordinary year 
	return 0;                                         // return  0
}

The code has been explained clearly through comments , I can't describe more here , This code is also a very simple code , By reading the code , Then change the code , I'll write the code myself when I have time , You can learn to write code slowly . Everyone said C Is the most basic language , If you learn C Language , Then you can learn other programming languages , meanwhile , There are specialized skills , At most, we are proficient in 1-2 Languages , Train yourself for a long time , Can become more and more powerful , Other languages , We can understand it , After all, our time and energy are limited .

The following is the operation interface ： 

 OK, The above is the learning of this simple code , We are all training , Train your ability , When you have time, open the computer and type a code , Slowly , Will become more and more skilled , In the future, I can engage in software development .

Now let's share the first 3 Code ：

#include <stdio.h>

// Definition pi by 3.14
#define pi 3.14

// Statement findCircumference() function 
double findCircumference(double r);
double findArea(double r);

int main() {
    double c;    // Define the circumference of the circle 
    double r;    // Define the radius of the circle 
    double s;
    // Of course, it can also be written in the following form 
    //float c,r;

    printf("Please input the radius:");     // Give a prompt for what you need to enter 
    scanf("%lf",&r);                        // Read the entered radius length from the keyboard 
    c=findCircumference(r);
	s=findArea(r);                 // call findCircumference() function , Pass the value of radius into this function , Calculate the circumference of a circle , And assign the result to the variable c
    printf("The circumference is: %.2lf\n",c);  // Print the circumference of the circle on the screen 
    printf("The area is:%.2lf",s);
	return 0;                               // End procedure 
}

/**
 *  This function is used to calculate the circumference of a circle 
 *  The parameter passed in is the radius of the circle 
 *  The returned parameter is the length of the circle 
 */
double findCircumference(double r){
    double c;   // Define the circumference of the circle , local variable , Only valid in this function 
    c=2*pi*r;   // Calculate the circumference of a circle 
    return c;   // Return the circumference of the circle 
}

double findArea(double r){
    double s;   // Define the area of the circle , local variable , Only valid in this function 
    s=pi*r*r;   // Calculate the area of a circle  
    return s;   // Returns the area of the circle  
}

Or that sentence , There are specialized skills , Our time and energy are limited , We need a long time of immersive programming , Some students may like programming very much , Some students don't like it very much , therefore , It still depends on personal interests , therefore , Find your own interests , Just study for decades , Take it as a skill of your own , You can even make your skills feel artistic .

OK, Thank you for your browsing , thank you all . I will continue to learn C Language , There is embedded software development , Try to make some interesting embedded systems to share with you , I am also constantly learning , meanwhile , I will insist on writing blog, Strive for better and better content , At the same time, writing skills continue to improve , Improve the excellence of the content and the readability of the document , Try to bring you different feelings .