Process Control in C

First, Process Control

L Sequential structure: the default process structure. Each statement is executed in the written order.

L Select structure: Judge the given condition and decide which code to execute according to the result of judgment.

L Loop Structure: Executes a piece of code repeatedly when a given condition is true.

Second, choose the structure-IF1. Simple to use

L if ( expression ) statement 1;

u if (count>50) classes ; class ;

L if ( expression ) statement 1; else statement 2;

U f (count>50) classes ; Else no classes ;

L if ( expression ) {}

u if (count>50) { classes ; Classroom Arrangement  ;} else {}

Scope of the U {}

L If-else If-else

u if(a==0) else if (a>0) Else

U features: Only one parenthesis will be executed

L Compound Condition

U value range for class time (9~12 | | ~17)

L Traps

u if (a!=0) {A is not 0;} else {a is 0;}

U if (a); {  }

u if (a=0)

u a = = 0;

U if (ten) int a = 9;

2. Exercises

1> Enter an integer day to represent the day of the week, according to the value of day to output the corresponding day of the week, such as day==1, the output "Monday"

2> Enter an integer , month, to represent the month, according to the month output corresponding to the season.

Spring:3,4,5

Summer:6,7,8

Autumn:9,ten, One

Winter:1,2

3> Enter an integer score to represent the score, based on the score output level (a-e)( in two ways )

A:90~100

B:80~89

C:70~79

D:60~69

E:0~60

Third, choose the structure-switch1. Simple to use

L-Switch ( expression ) { case value 1:break; ... default:break;}

l Example

int a = 10;

Switch (a) {

Case 0:

printf (" This is a 0");

Break

Case 5:

printf (" This is a 5");

Break

Case 10:

printf (" This is a ten");

Break

Default

printf (" nothing ");

Break

}

L briefly describe the role of break

L define variables in case

2. Ifand theSwitchthe contrast

L Many situations can be interchanged

L if used more, more flexible,switch can only a single value

3. Exercises

Use switch instead of if to implement the problem in if

IV. cyclic structure-while1. Simple to use

L Continuous printf ("push-ups") for three times ;

L while ( expression ) {}

L Continue: Output 5 times take a break.

L use of break: Stop the loop at some time

2. Features

The loop body is executed only if the condition is established.

3. Exercises

1> prompts the user to enter a positive integer n, computes 1+2+3+... +n and

2> prompts the user to enter a positive integer n, computes 1-2+3-4+5-6+... +n and

4. Traps

while ( condition );

V. Structure of circulation-do while

L Features: Must be executed once the body of the loop

L while and do While loop comparison

int i=0;
while (i<0) {
i++;
}

int i=0;
do{
i++;
} while (i<0);

VI. Structure of circulation-for1. Simple and practical

L Running Process

L Initialization statements can be multiple sentences (place printf in the for parentheses)

2. ForLoop Nesting

Friends List 1

Friends 1

Friends 2

Friends List 2

Friends 1

Friends 2

Friends List 3

Friends 1

Friends 2

3. Traps

1> dead loop for (;;);

2> scope of internal variables for the for loop body

3> Scope Confusion

for (int i = 0; i<5; i++) int a = 10;

4. WhileLoops and forComparison of Loops

L can be interchangeable

L for loop variables can be recovered in time

5. Exercises

1> prompts the user to enter a positive integer n, if n5, outputs the following graph, the other n values , and so on

2> Output 99 Multiplication table

Seven, breakand theContinue1. Break

L Use occasion:switch\ cycle Structure

L break under Nested loops

2. Continue

L Application: Cyclic structure

L continue under cyclic nesting

Process Control in C