520. Detect Capital（python+cpp）

题目：

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:

1. All letters in this word are capitals, like “USA”.
   2.All letters in this word are not capitals, like “leetcode”.
   3.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 

Note: The input will be a non-empty word consisting of uppercase and lowercase latin letters.

解释：
判断拼写是否正确
python代码：

class Solution(object):
    def detectCapitalUse(self, word):
        """
        :type word: str
        :rtype: bool
        """
        if word.isupper():
            return True
        elif word.islower():
            return True
        elif word==word.capitalize():
            return True
        return False                

c++代码：

#include <cctype>
class Solution {
public:
    bool detectCapitalUse(string word) {
        int  cnt=0;
        for (auto c:word)
            if (isupper(c))
                cnt+=1;
        return (cnt==0 ||cnt==word.size() || (cnt==1 && isupper(word[0])));  
    }
};

总结：
pythoncapitalize()将字符串的第一个字母变成大写,其他字母变小写。
python 的 isupper() islower() upper() lower()函数。
c++ <cctype>中的 isupper()函数，toupper()和tolower()在C++中定义分别在std和<cctype>中。
c++中实现大小写转换：

#include <iostream>
#include <string>
#include <cctype>
#include <algorithm>
using namespace std;
int main()
{
    string s = "Hello World";
    cout << s << endl;
    transform(s.begin(),s.end(),s.begin(),::toupper);
    cout << s << endl;
    transform(s.begin(),s.end(),s.begin(),::tolower);
    cout << s << endl;
    return 0;
}