Java Program Flow Control

I. Sequential structure

Sequential structure is the most basic process control of a program, there is no specific grammatical structure, followed by top-down execution.

II. selection structure (branching structure)

1, If-else statement

if (conditional expression) {/* Determines whether the conditional expression is true, and if true, executes the contents of the code block;

Executes a block of code, and executes a block of code, jumps out of the If-else statement, and is bound to execute one;

}else if (conditional code block) {/* If the execution statement has only one {} can be omitted.

Execute code block;

}

.........

else{

Execute code block;

}

2, switch statement

Switch (variable) {/* variable: char byte short int Sting enumeration;

Case value 1: * No break, will continue to execute;

The default statement indicates that when all cases do not match, the

Case value 2: * content;

break; * Default position can be swapped, but always the last one executed.

... * * Only constants are behind the case.

Default

Break

}

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+ Keyboard input data

(1) Guide package: Import Java.util.Scanner;

(2) Create an object of the Scanner class: Scanner s = new Scanner (system.in);

Sysout Tips keyboard input what things;

(3) The object to invoke the secondary input: String st = S.next (); String

int i = S.nextint (); Integer

Three, cycle structure

1, for Loop statement

for (initialization condition; loop condition; iteration condition) {

Circulation body;

}//Until the loop condition is not satisfied, exit the loop.

Egg:for (int=1;i<=100;i++) {

System.out.print (i + "t");

} The traversal of natural numbers within//100;

Difference between 2, while loop/* for loop and while loop

initialization condition; * The initialization condition of the for loop can no longer be used in the loop;

while (loop condition) {*/While the initialization condition of the loop is also available for looping.

Circulation body;

iterative conditions;

}

3, do While loop/* Whlie loop and do While loop difference

The initialization condition; * Does while looping at least once;

do{* * While loop does not.

Circulation body;

iterative conditions;

}while (cyclic condition)

4, Infinite cycle

(1) for (;;) {}//break jumps out of the current loop;

(2) while (true) {}//continue jumps out of the secondary loop.

5, nested loop (equivalent to the inner loop as a whole loop of the outer loop body)

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Java Program Flow Control