练习21: 函式的返回值–笨方法学ruby在线

你已经学过使用=给变量命名，以及将变量定义为某个数字换字符串。接下来我们将让你见证更多奇迹。我们要示范给你的是如何使用=来将变量设置为「一个函式的值」。有一件事你需要特别注意，但待会再说，先输入下面的脚本吧：

def add<span class="o">(</span>a, b<span class="o">)</span> puts <span class="s2">"ADDING #{a} + #{b}"</span> a + b end def subtract<span class="o">(</span>a, b<span class="o">)</span> puts <span class="s2">"SUBTRACTING #{a} - #{b}"</span> a - b end def multiply<span class="o">(</span>a, b<span class="o">)</span> puts <span class="s2">"MULTIPLYING #{a} * #{b}"</span> a * b end def divide<span class="o">(</span>a, b<span class="o">)</span> puts <span class="s2">"DIVIDING #{a} / #{b}"</span> a / b end puts <span class="s2">"Let's do some math with just functions!"</span> <span class="nv">age</span> <span class="o">=</span> add<span class="o">(</span>30, 5<span class="o">)</span> <span class="nv">height</span> <span class="o">=</span> subtract<span class="o">(</span>78,4<span class="o">)</span> <span class="nv">weight</span> <span class="o">=</span> multiply<span class="o">(</span>90, 2<span class="o">)</span> <span class="nv">iq</span> <span class="o">=</span> divide<span class="o">(</span>100, 2<span class="o">)</span> puts <span class="s2">"Age: #{age}, Height: #{height}, Weight: #{weight}, IQ: #{iq}"</span> <span class="c"># A puzzle for the extra credit, type it in anyway.</span> puts <span class="s2">"Here is a puzzle."</span> <span class="nv">what</span> <span class="o">=</span> add<span class="o">(</span>age, subtract<span class="o">(</span>height, multiply<span class="o">(</span>weight, divide<span class="o">(</span>iq, 2<span class="o">))))</span> puts <span class="s2">"That becomes: #{what} Can you do it by hand?"</span>

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def add<span class="o">(</span>a, b<span class="o">)</span>   puts <span class="s2">"ADDING #{a} + #{b}"</span>   a + b end   def subtract<span class="o">(</span>a, b<span class="o">)</span>   puts <span class="s2">"SUBTRACTING #{a} - #{b}"</span>   a - b end   def multiply<span class="o">(</span>a, b<span class="o">)</span>   puts <span class="s2">"MULTIPLYING #{a} * #{b}"</span>   a * b end   def divide<span class="o">(</span>a, b<span class="o">)</span>   puts <span class="s2">"DIVIDING #{a} / #{b}"</span>   a / b end   puts <span class="s2">"Let's do some math with just functions!"</span>   <span class="nv">age</span> <span class="o">=</span> add<span class="o">(</span>30, 5<span class="o">)</span> <span class="nv">height</span> <span class="o">=</span> subtract<span class="o">(</span>78,4<span class="o">)</span> <span class="nv">weight</span> <span class="o">=</span> multiply<span class="o">(</span>90, 2<span class="o">)</span> <span class="nv">iq</span> <span class="o">=</span> divide<span class="o">(</span>100, 2<span class="o">)</span>   puts <span class="s2">"Age: #{age}, Height: #{height}, Weight: #{weight}, IQ: #{iq}"</span>   <span class="c"># A puzzle for the extra credit, type it in anyway.</span> puts <span class="s2">"Here is a puzzle."</span>   <span class="nv">what</span> <span class="o">=</span> add<span class="o">(</span>age, subtract<span class="o">(</span>height, multiply<span class="o">(</span>weight, divide<span class="o">(</span>iq, 2<span class="o">))))</span>   puts <span class="s2">"That becomes: #{what} Can you do it by hand?"</span>

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