LeetCode-Easy部分中标签为String 520. Detect Capital

Given a word, you need to judge whether the usage of capitals in it is right or not.

We define the usage of capitals in a word to be right when one of the following cases holds:

All letters in this word are capitals, like “USA”.
All letters in this word are not capitals, like “leetcode”.
Only the first letter in this word is capital if it has more than one letter, like “Google”.
Otherwise, we define that this word doesn’t use capitals in a right way.

Example 1:
Input: "USA"
Output: True

Example 2:
Input: "FlaG"
Output: False

代码分析

所有字母大写，只有首字母为大写，所有字符小写，这是三种合法的字符。判断根据这个思路去写即可。

代码实现

        public bool DetectCapitalUse(string word)
        {
            if (string.IsNullOrEmpty(word)) return true;

            char fst = word[0];
            if(charCapital(fst))
            {
                int afterCapital = 0;
                for(int i=1;i<word.Length;i++)
                {
                    if (charCapital(word[i]))
                        afterCapital++;
                }
                if (afterCapital == 0)
                    return true;//只有首字符大写
               else if (afterCapital == word.Length - 1)
                   return true;//都是大写
                return false;
            }
            else//首字符小写
            {
                int afterCapotal=0;
                for (int i = 1; i < word.Length; i++)
                {
                    if(charCapital(word[i]))
                        afterCapotal++;
                }
                return afterCapotal == 0 ? true : false;
            }

        }

判断字符是否为大写

        private bool charCapital(char ch)
        {
            int chint = Convert.ToInt32(ch);
            if (chint >= 65 && chint <= 90)
                return true;
            return false;
        }

更多string题目

http://blog.csdn.net/daigualu/article/details/69566863