Update 12.1.md

eBook/12.1.md

@@ -129,19 +129,16 @@ func main() {
 
 **练习**
 
-**Exercise 12.1:** word_letter_count.go
-Write a program which reads text from the keybord. When the user enters ‘S’ in order to signal the end of the input, the program shows 3 numbers:
-i) the number of characters including spaces (but excluding ‘\r’ and ‘\n’)
-ii) the number of words
-iii) the number of lines
+**练习 12.1:** word_letter_count.go  
+编写一个程序，从键盘读取输入。当用户输入 'S' 的时候表示输入结束，这时程序输出 3 个数字：  
+i) 输入的字符的个数，包括空格，但不包括 '\r' 和 '\n'
+ii) 输入的单词的个数
+iii) 输入的行数
 
-**Exercise 12.2:** calculator.go
-Make a simple (reverse polish notation) calculator. This program accepts input from the user in the
-form of integers (maximum 999999) and operators (+, -, *, /).
-
-The input is like this: number1 ENTER number2 ENTER operator ENTER result is displayed.
-
-The programs stops if the user inputs “q”. Use the package stack you developed in Ex. 11.3
+**练习 12.2:** calculator.go
+编写一个简单的逆波兰式计算器，它接受用户输入的整型数（最大值 999999）和运算符 +、-、*、/。
+输入的格式为：number1 ENTER number2 ENTER operator ENTER --> 显示结果
+当用户输入字符 'q' 时，程序结束。请使用您在练习11.3中开发的 `stack` 包。
 
 
 ## 链接