C Language Basics Lesson---------basic data types, constants, variables

int main () {

Single-line comment: Comment Line

/*

Multiline Comment: Within this interval, it is a multi-line comment that can be wrapped.

*/

#pragma mark---basic data type----

/*

Char character type contains: ' A~z ' a~z ' 0~9 ' and so on

int integral type contains: number 1234567890, etc.

Float Float type contains: Number 1.2 2.5 and so on

Short shorter integer contains: number 123456789, etc.

Long length shaping includes: number 123456789, etc.

Double-progress floating-point type contains: Number 1.1 2.2 3.3 and so on

*/

/*

Binary: Rounding mechanism

decimal-to-n-binary: Even removing the rewind method

N-Decimal: Weighted summation method

*/

#pragma mark----constants, variables-------

Constants: The amount of values that can not be changed during a program run;

integer constant; 10 12 15 and so on.

Floating-point constants, 5.5 5.4, etc.

Character type constant: ' A ' a ' 5 '

Variables: The amount of values that can change during a program's run

/*

Define variables: Consists of three parts: type modifier variable name = initial value

*/

Example: Define an integer variable named age with an initial value of 20;

int age= 20;

Define a character variable named name and the initial value is w;

Char name = ' W ';

Defines a single-precision floating-point variable named cost with an initial value of 1.2;

float cost = 1.2;

Define a short integer variable named a with an initial value of 10;

Short a=10;

Defines a double-precision floating-point variable with a variable named T and an initial value of 22.02;

Double t=22.02;

Defines a long integer variable named B with an initial value of 1234;

Long b= 1234;

Age = 29;

name = ' h ';

Cost = 2.2;

A = 3;

t = 2.3;

b = 123;

1. Variable names consist of numbers, letters, underscores, and cannot begin with a number;

int 3a=0;

int a3_=0;

int _3a=0;

2. Cannot have the same name as the system reserved word

int int=0;

int return=0;

3. Cannot use duplicate variable names

int f=0;

int f=5;

4. See the name (Code specification)

FLOAT score = 98.5;

int age = 9;

int myAge = 29;

int/**/a=0;

in/**/t

C Language Basics Lesson---------basic data types, constants, variables