Author name: 1_bit introduction: CSDN blog expert, 2020 TOP5 blog stars

🐰 Xiaoc: Xiaoyuan, let’s continue our class.

👸 Xiaoyuan: Ok, xiaoyuan, I can’t wait. 😉

🐰 Small C: I would like to ask you a few questions first, do you think our variable can store integer type, what else can store similar?

👸 Xiaoyuan: Ah… I don’t know. I don’t know. 😱

🐰 small C: That I change a question to ask you, mathematics in addition to integer still have what number?

👸 Yuan: And decimals.

🐰 Little C: What about decimals that can be put into integer variables?

👸 small yuan: should, can’t? 😭

🐰 small C: can put, but will give a problem. Int is an integer type, but we have another type that represents a decimal, and of course the decimal is in quotation marks, so we use that for your convenience.

👸 xiaoyuan: What is that with what to express decimal?

🐰 small C: Use float to represent decimals, but in C we should call it floating point.

👸 xiaoyuan: that is not equal to creating a floating point variable. 😥

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
} 
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🐰 small C: Yes, then you write a program output display try.

👸 small yuan: I always feel you pit me, you see is not so. 😩

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
	printf("%d",a);
} 
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🐰 Small C: You try first.

👸 Xiaoyuan: Ah, why so. 😓

🐰 little C: That’s because %d is also an integer and we should use %f instead of %d. Try this instead.

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
	printf("%f",a);
} 
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👸 small yuan: wow, successful, that why behind have a few 0 follow? 😉

🐰 small C: This is because 0 is its default display digit, which we can ignore. Now that you’ve learned about the different types of representations, I’m going to show you how to add two numbers together in C and get the result. Look at the following program.

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
	int b=10;
	printf("%f",a+b);
} 
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👸 xiaoyuan: Huh? Will %f also be replaced by the value of a plus b?

🐰 little C: Yes, when printf is executed, the result of a+b will be computed first, and finally the result of a+b will be displayed at %f.

👸 xiaoyuan: that why is % F?

🐰 Small C: I ask you 3.14+10 is what?

👸 Yuan: 13.14, what’s wrong? 😩

🐰 small C: 13.14 is not a decimal number?

👸 Xiaoyuan: I see, the final result is a decimal, so use %f. No, I should say floating point. 😨

🐰 small C: ha ha ha, yes, let me ask you, I want you to display the value of a+b and b-a at the same time, how will you do it?

👸 Xiaoyuan: HMM… I think… Got it. Look at the code.

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
	int b=10;
	printf("%f,%f",a+b,b-a);
} 
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🐰 small C: good, or quite smart, know to use a comma separated, so there are two values. So let me ask you again if I want to store the results of a plus b and b minus A in a variable, and then print them out what do I do?

👸 small yuan: this can not difficult me, you see the code. 😃

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
	int b=10;
	float c=0,d=0;
	c=a+b;
	d=b-a;
	printf("%f,%f",c,d);
} 
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🐰 small C: it seems that you still can, but your code can be simplified, you see my code you think is not more simplified.

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14,c=0,d=0;
	int b=10;
	c=a+b;
	d=b-a;
	printf("%f,%f",c,d);
} 
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👸 small yuan: so I also can. 😃

🐰 Little C: You can do that.

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
	int b=10;
	float c=a+b;
	float d=b-a;
	printf("%f,%f",c,d);
} 
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👸 Xiaoyuan: the original can directly create a variable when you can add assignment? ☺ ️

🐰 Little C: Yes, but remember, programs run from the top down, just like you read a book. To use a variable you have to declare the creation beforehand, or our compiler won’t know what it is.

👸 xiaoyuan: well, like reading a novel, inexplicable appearance of a character, if there is no introduction in front of that I do not know him.

🐰 Little C: Yes. Let me show you how to add, subtract, multiply and divide again.

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
	int b=10;
	float c=a+b;
	float d=b-a;
	float e=b*a;
	float f=b/a;
	printf("%f,%f",c,d);
} 
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👸 Xiaoyuan: very easy, with math in the same. 😇

🐰 Little C: Of course, you can also mix calculations.

#include<stdio.h>
#include<stdlib.h>
void main(a){
	float a=3.14;
	int b=10,a1=1,a2=8;
	float c=a+b-a1;
	float d=b-a*a2;
	float e=b*a+a1;
	float f=b/a*b;
	printf("%f,%f",c,d);
} 
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👸 small yuan: feel the content of today’s study is very simple, ha ha ha, is not I enlightened.

🐰 small C: today indeed you perform better, make persistent efforts, we will continue to learn tomorrow.

👸 Xiaoyuan: OK, then I go back to practice. 😋

🐰 C: Come on.