|  | @@ -370,6 +370,21 @@ namespace OTSPartA_STDEditor
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				|  |  |                          MessageBox.Show("Invalid string exists:" + "(" + Symbol[i], "Tip", MessageBoxButtons.OK, MessageBoxIcon.Information);
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				|  |  |                          return false;
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				|  |  |                      }
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				|  |  | +                    //尾字符检测
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				|  |  | +                    int n= Symbol[i].Length;
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				|  |  | +                    if (str_RemoveBlank.Length >= n)
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				|  |  | +                    {
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				|  |  | +                        if (str_RemoveBlank.Substring(str_RemoveBlank.Length-n, n) == Symbol[i]) 
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				|  |  | +                        {
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				|  |  | +                            MessageBox.Show("Last character is error!", "Tip", MessageBoxButtons.OK, MessageBoxIcon.Information);
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				|  |  | +                            return false;
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				|  |  | +                        }
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				|  |  | +                        if (str_RemoveBlank.Substring(0, n) == Symbol[i])
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				|  |  | +                        {
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				|  |  | +                            MessageBox.Show("First character is error!", "Tip", MessageBoxButtons.OK, MessageBoxIcon.Information);
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				|  |  | +                            return false;
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				|  |  | +                        }
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				|  |  | +                    }
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				|  |  |                  }
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				|  |  |  
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				|  |  |                  //左右括号匹配检验
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				|  | @@ -384,21 +399,21 @@ namespace OTSPartA_STDEditor
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				|  |  |                      MessageBox.Show("Number of left and right parentheses does not match!", "Tip", MessageBoxButtons.OK, MessageBoxIcon.Information);
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				|  |  |                      return false;
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				|  |  |                  }
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				|  |  | -                //首字符检测
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				|  |  | -                if ((str_RemoveBlank[0] == '+') || (str_RemoveBlank[0] == '-') || (str_RemoveBlank[0] == '*') || (str_RemoveBlank[0] == '/') || (str_RemoveBlank[0] == '>') || (str_RemoveBlank[0] == '<') || (str_RemoveBlank[0] == '=') || (str_RemoveBlank[0] == ')') || (str_RemoveBlank[str_RemoveBlank.Length - 1] == '('))
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				|  |  | -                {
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				|  |  | -                    MessageBox.Show("First character is error!", "Tip", MessageBoxButtons.OK, MessageBoxIcon.Information);
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				|  |  | -                    return false;
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				|  |  | -                }
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				|  |  | -
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				|  |  | -                if (str_RemoveBlank.Length >= 3)
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				|  |  | -                {
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				|  |  | -                    if ((str_RemoveBlank.Substring(0, 3) == "and") || (str_RemoveBlank.Substring(0, 3) == "end"))
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				|  |  | -                    {
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				|  |  | -                        MessageBox.Show("First character is error!", "Tip", MessageBoxButtons.OK, MessageBoxIcon.Information);
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				|  |  | -                        return false;
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				|  |  | -                    }
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				|  |  | -                }
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				|  |  | +                ////首字符检测
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				|  |  | +                //if ((str_RemoveBlank[0] == '+') || (str_RemoveBlank[0] == '-') || (str_RemoveBlank[0] == '*') || (str_RemoveBlank[0] == '/') || (str_RemoveBlank[0] == '>') || (str_RemoveBlank[0] == '<') || (str_RemoveBlank[0] == '=') || (str_RemoveBlank[0] == ')') || (str_RemoveBlank[str_RemoveBlank.Length - 1] == '('))
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				|  |  | +                //{
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				|  |  | +                //    MessageBox.Show("First character is error!", "Tip", MessageBoxButtons.OK, MessageBoxIcon.Information);
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				|  |  | +                //    return false;
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				|  |  | +                //}
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				|  |  | +
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				|  |  | +                //if (str_RemoveBlank.Length >= 3)
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				|  |  | +                //{
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				|  |  | +                //    if ((str_RemoveBlank.Substring(0, 3) == "and") || (str_RemoveBlank.Substring(0, 3) == "end"))
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				|  |  | +                //    {
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				|  |  | +                //        MessageBox.Show("First character is error!", "Tip", MessageBoxButtons.OK, MessageBoxIcon.Information);
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				|  |  | +                //        return false;
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				|  |  | +                //    }
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				|  |  | +                //}
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				|  |  |  
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				|  |  |  
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				|  |  |                  //forth_elem干扰or分隔符,故先行去掉
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