This is the 11th day of my participation in the August More Text Challenge. For details, see:August is more challenging
- variable
- The operator
- C language statement
- An array of
- function
- Pointer to the
- The structure of the body
05 Part Five Variables
Variables are the quantities that can be changed during the running of the program, such as y,z,w, etc.
- Definition method:
Data type variable 1[, variable 2…] For example:
int a=0;
double b=0.23;
charS = 'A';int *a =0x2323;
Copy the code- Initialization: An initial value is given when defined
- Position of variable definition: usually at the beginning of the function
06 Part Six operator
Arithmetic operator
Assuming variable A = 10 and variable B = 20, then:
An operator
The bitwise and &, bitwise or | and bitwise exclusive or ^ truth table is as follows:
Assignment operator
The assignment operator assigns the value on the right to the variable on the left.
Other operators
In addition, there are relational operators, namely >, ≥, ≤, <,! =, == (what is an equal sign? Two equals again?) In which, the first four take precedence over the last two. In particular, the priority is from high to low. Arithmetic operator > relational operator > assignment operator
Part Seven C language statements
C Statement type
C language is divided into the following five categories:
- Control statement: such as loop statement while, for, such as conditional statement if, such as branch statement switch.
- Function call statement: consists of a function call plus a semicolon.
int main(a)
{ int Min(int a,int b){
if(a>b){
returnb; }else{returna; }}}Copy the code- Expression statement: Add a semicolon to the end of an expression, such as assignment statement a=a+1.
- Empty statement: A statement that contains only one semicolon, that is, {}.
- Compound statement: A sequence of statements enclosed by curly braces {}.
Control statements
If statement:
- sample
{/ statement to execute if the expression is true /}
- For example:
main(){
int a=1, b=2;
if(a < b) { ++a; }}
Copy the code- Result: if a is less than B, a increases by 1 and becomes 2.
If else statement:
- sample
If (expression){/ statement that will execute if the expression is true /} else{/ statement that will execute if the expression is false /}
- For example,
main(){
int a=1, b=2;
if(a < b) { ++a; }
else{a*=4; }}Copy the code- Result: if a is less than b, then a increases by 1 and becomes 2; otherwise, a is equal to a times 4.
Goto statement
Break statement:
- For example:
for(int i=0; i<N; ++i){
if(i == 2)
break;
}
Copy the code- Result: The loop is terminated directly when I is 2.
The continue statement:
- For example,
for(int i=0; i<N; ++i){
if(i == 2)
continue; }Copy the code- Result: When I is 2, this cycle is finished and the next decision is made.
08 Part Eight Array
An array of concepts
- Int a[100]; // Define an array of 100 integers; • Array: an ordered collection of data elements of the same type;
- 1. The name common to an array;
- 2. A variable in a collection;
- Array dimension: The number of subscripts following the array name;
- Array element format: array name [subscript];
- Array definition: < data type > < Array name >[< constant expression >]={< initial value >}
A few points to note
Int a[5]={1,2,3}; //a[0]=1,a[1]=2,a[2]=3,a[3]=0,a[4]=0. Note: Arrays can be defined and initialized, not defined and initialized, as follows:
