First Identity C Language 2021.10.19

Today's learning capacity is somewhat large, here it is necessary to comb what you have learned today.   

Catalog

First, the first choice statement

2. First Identity Circular Sentences

3. Functions

4. Arrays

5. Operators

6. Keyword

First, the first choice statement

There are many choices in life, no matter right or wrong, you should not regret the choices you made.

Select the statement as follows

#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
int main()
{
	int input = 0;
	printf("Do you want to study hard?(1/0)");
	scanf("%d", &input);
	if(input==1)
	{
		printf("good offer");
	}
		else
    {

		printf("Sell sweet potatoes\n");
    }

	return 0;
}

Whether we get a good offer or not, we should continue to expand our knowledge reserve or we may only be able to "sell sweet potatoes".   ūüėÜ

2. First Identity Circular Sentences

Some things have to be done all the time, and they go on and on, like learning

In C, loop statements are     the while statement

                                          for statement  

                                          Do... While statement

Since the title of this article is "First-time C Language", we will introduce the while cycle first today and then the other two later periods.

There are the following codes

#include <stdio.h>
int main()
{
	int line = 0;
	while (line < 30000)
	{
		printf("Continue writing code:%d\n", line);
		line++;//line=line+1 can also be used here
	}
	if (line == 30000)
		printf("good offer\n");
	return 0;
}

When certain conditions are met, the loop stops

3. Functions

C language, some independent functions can also be encapsulated into a function

#include <stdio.h>
int main()
{
    int num1 = 0;
    int num2 = 0;
    int sum = 0;
    printf("Enter two operands");
    scanf("%d %d", &num1, &num2);
    sum = num1 + num2;
    printf("sum = %d\n", sum);
    return 0;
}
The code above is written as a function as follows:
#include <stdio.h>
int Add(int x, int y)
{
   int z = x+y;
   return z;
}
int main()
{
    int num1 = 0;
   int num2 = 0;
    int sum = 0;
    printf("Enter two operands:>");
    scanf("%d %d", &num1, &num2);
    sum = Add(num1, num2);
    printf("sum = %d\n", sum);
    return 0;
}

  The code above shows the first as a normal sum and the second as a function sum.

Where the function must be defined

 

  4. Arrays

How do I store 1-10 numbers?

Arrays are defined in C: a set of elements of the same type

int arr[10] = {1,2,3,4,5,6,7,8,9,10};// Define an integer array with up to 10 elements

Subscript of array

Language C specifies that each element of an array has a subscript, which starts with 0. Arrays can be accessed through subscripts.

such as

int arr[10] = {0}; // If the array has 10 elements, the subscript range is 0-9

int  arr [10]0000000000
subscript0123456789

Use of arrays

int main()
{
	int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
	int i = 0;//Use i to generate Subscripts
	while (i < 10)
	{
			printf("%d", arr[i]);
			i++;
     }
	return 0;
 }

  If you want to print an array

  Character Array

char ch[5]={'a','b','c'};

This is not fully initialized, the remaining two elements default to 0

char ch[6]={"hello"}

  So much for arrays.

5. Operators

1. Arithmetic Operators

+      -      *      /      %

Here are the main descriptions/and%

/:divide

An example: 9/2=4

The reason is that both sides of'/'are integers, dividing by integers, whether int or float, results in 4

Solution: 9/2.0 or 9.0/2     Results 4.500000

2. Shift Operators

>>                     << 

  Here's an example of moving left

The result is

Reason:  

 

  By 1*2^1=2   Change to 1*2^2=4

  3. Bit Operators

&               ^                  |

Bitwise and (0 for binary bits, 1 for all)

|   Bitwise or   (11 for all 0)

^   Bitwise XOR (same 0, dissimilar 1)

Here's an ex amp le

  So why is the result 1?

4. Assignment Operators

=    +=     -=     *=    /=    &=    ^=     |=       >>=      <<= 

5. Monocular Operators

a+b has two operands, so + is a binocular operator

!           Logical Inverse Operation

-           negative

+           Positive

&           Take Address

sizeof       Type length of operand in bytes

~           Bitwise negation of a number

--              Front and rear  --

++.           Front and rear  ++

*           Indirect access operator (dereference operator)

(type)       Mandatory Type Conversion

 

(1)--              Front and rear  --

         ++           Front and rear  ++

The first is to use++ first, the second is to use++.

int main()
{
int a=10;
intb=a++
printf ("%d %d",a,b);

return 0;
}

Results: 11,10

(2)   (type)       Mandatory Type Conversion

int main()
{
int n=3.14Ôľõ
int n=(int)3.14
return 0;
}

6. Relational Operators

>

>=

<

<=

!=       Used to test "inequality"

==       Used to test equality

  7. Logical Operators

&&         Logical and  

||           Logical or

 

&&         Logical and   (and)

||           Logical or   (or)

8. Conditional Operators (Trinomial Operators)

exp1 ? exp2 : exp3

Function: Simplify if statement

#include<stdio.h>
int main()
{
	int a = 0;
	int b = 0;
	int max = 0;
    scanf("%d%d",&a,&b);
    if(a>b)
    max=a;
    else
    max=b;
	printf("%d\n", max);
   return 0;
}

//Use Conditional Operators
#include<stdio.h>
int main()
{
	int a = 0;
	int b = 0;
	int max = 0;
    scanf("%d%d",&a,&b);
    max=(a>b?a;b;);
	printf("%d\n", max);
   return 0;
}

 exp1 ? exp2 : exp3

Expression 1 turns true, expression 2 does not count 3, and expression 2 turns out to be

Expression 1 results in false, expression 3 calculates 2 does not, and expression 3 results in false

9. Comma expression (calculated from left to right, but the result of the whole expression is the result of the last expression)

exp1, exp2, exp3, ...expN

int main()
{
	int a = 3;
	int b = 5;
	int c = 10;
	int d = (a + 2, b = a - 3, c = b + 4);
	printf("%d\n", d);
return 0;
}

 

 (b=0,c=4) -> d=0+4=4

10. Subscript references, function calls, and structure members

[]      ()      .       ->

  6. Keyword

auto  break   case  char  const   continue  default  do   double else  enum   extern float  for   goto  if   int   long  register    return   short  signed sizeof   static struct  switch  typedef union  unsigned   void  volatile  while 

Auto-auto-define automatic variable

const-Modify constant variable, Modify pointer

 

Keyword typedef

typedef, as its name implies, is a type definition, which should be understood here as type renaming

 

//Rename unsigned int to uint_32, so uint_32 is also a type name
typedef unsigned int uint_32;
int main()
{
    //Looking at num1 and num2, the two variables are of the same type
    unsigned int num1 = 0;
    uint_32 num2 = 0;
    return 0;
}

It's 0:48 on October 20th. After more than two hours, I finally finished this blog and am ready to sleep. Good night!! ‚ú®‚ú®

Keywords: C

Added by StevenJ on Tue, 19 Oct 2021 19:15:10 +0300