Java Foundation Chapter III

First, basic if structure

1. Flowchart

Input/Output

Judging and branching

Process Line

1.1 Simple if condition to judge

if ( expression ) {

                                 // expression is true , execute the code in {}

}

1.2 Simple if condition to judge

if ( expression ) {

// expression is true , execute here

}else{

                                      // expression is false , this line here

}

Description: If the If or else is followed by, and there is only one line of code, {} can be omitted, but it is not recommended to omit

Second, logical operators

&& Logic and (press shift+7)--and (and, at the same time)

Multiple conditions, 1 are false, if () all false, multiple conditions are true at the same time, if () is true

                       || (Press shift+ to enter the above |) -or (OR)

Multiple conditions, as long as 1 are true, if () all is true

                      ! (in English state)--Take the inverse not equal to! =

determine if strings are equal  

A , case-sensitive: password

String Variables . equals ( value of string or string variable )

B , Case insensitive: Verification Code

String Variables . Equalsignorecase ( value of string or string variable )

How do I break down numbers in bits, 10, hundred, thousand? "P47"

Int digit = number% 10//decomposition get single digit

Int 10 bit = number/10 10//decomposition get 10 digits

Int hundred = number/100% 10//decomposition to get the number of hundred

INT thousand = number/1000% 10//Decomposition get thousand

Third, multiple if structure

if ( condition 1) {

                              // code block

}else if ( condition 2) {

                              // code block

}else if ( condition N) {

                              // code block

} else{

                              // code block

}

Description: An else if can have multiple, sequential requirements on the number range

in the I f Input String--if ( variable name . Equals (" string ")) {}

Iv. Nested IF structures

if ( condition 1) {

                         // code block

I f ( condition 1-1) {

}

Description: The if structure can be a if , If...else , multiple if and other structures

} else{

can be for if , If...else , multiple if and other structures

}

Java Foundation Chapter III