Question

if语句后面可以跟一个可选的else语句，该语句在表达式为false时执行。

语法 (Syntax)

MATLAB中if ... else语句的语法是 -

if <expression>
   % statement(s) will execute if the boolean expression is true 
   <statement(s)>
else
   <statement(s)>
   % statement(s) will execute if the boolean expression is false 
end

如果布尔表达式的计算结果为true，那么将执行if代码块，否则将执行代码块。

流程图 (Flow Diagram)

例子 (Example)

创建一个脚本文件并键入以下代码 -

a = 100;
% check the boolean condition 
   if a < 20 
      % if condition is true then print the following 
      fprintf('a is less than 20\n' );
   else
      % if condition is false then print the following 
      fprintf('a is not less than 20\n' );
   end
   fprintf('value of a is : %d\n', a);

编译并执行上述代码时，会产生以下结果 -

a is not less than 20
value of a is : 100