Conditional branch of Program Flow control (Delphi)

The if statement primarily detects a condition and executes a piece of code based on whether the condition is true or false;

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var  I: Integer;  FileGood: Boolean;begin  FileGood := True;  ifFileGood then{ 简洁的写法，判断FileGood是否为True}    ShowMessage(‘True‘);  { 上面的写法等同于下面}  ifFileGood = Truethen ShowMessage(‘True‘);  ifI > 0then{ 如果I大于0}    DoSomething1  elseifI < 0 then{ 如果I小于0，else if块不是必须的}    DoSomething2  else{ 如果是其他条件，通常来实现默认的处理，else块也不是必须的}    DoSomething;end;

The case statement can be thought of as the development of an if statement, which allows the program to execute a block of code in multiple blocks of code based on the result of an expression, which can only be of an ordered type variable as a condition factor, and the other, such as a string, is not feasible.

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var  I: Integer;begin  caseI of    1:      { 如果 I = 1}      DoSomething1;    2, 3:   { 如果 I = 2或者3，相当于if I in [2, 3]}      DoSomething2;    4..10:  { 如果 I在4到10范围内（含4和10）}      DoSomething3;  else{ 如果是其他条件，通常用来实现默认处理，else块也不是必须的}    DoSomething;  end;end;

Conditional branch of Program Flow control (Delphi)