为什么从字符串转换为int会导致奇怪的值(Why converting from string to int results in weird value)

 我是F＃的新手，我无法找到数字字符串的最后一个元素，并将该元素转换为int。 所以如果字符串是“123”，那么我想回到3.然而，这个代码： 
 
  let s (a : string) =
      let x = a.[0]
      int x
 
 这让我回到49，当我做s "123" 。 我无法弄清楚为什么会发生这种情况。 另外，当我输入字符串“124”时，它仍然给我49.有人可以解释为什么会发生这种情况，我该如何解决这个问题？ 

I'm new to F# and I was having trouble finding the last element of an number-string and converting that element to an int. So if the string was "123", then I would want to get back 3. However, this code:
 
  let s (a : string) =
      let x = a.[0]
      int x
 
This gives me back 49 when I do s "123". I can't figure out why this is happening. Also, when I input the string "124" it still gives me 49. Can someone explain why this is happening and how I can fix this?

原文：https://stackoverflow.com/questions/37463247