Length of Last Word

Description:

Given a string s consists of upper/lower-case alphabets and empty space characters ’ ‘, return the length

of last word in the string.

If the last word does not exist, return 0.

Note: A word is defined as a character sequence consists of non-space characters only.

For example, Given s = “Hello World”, return 5.

分析：

从后向前查找即可

代码：

#include <iostream>
#include <string>

using namespace std;

int LengthOfLastWord(string str) //从后向前读
{
int len = str.size();
int LastWordLen = 0;
int i = len - 1;
while ( i > 0 && str[i] == ' ') //跳过空格
--i;
while (i > 0 && str[i] != ' ')
{
i--;
LastWordLen++;
}

return LastWordLen;

}

int main()
{
string s = "Hello World   ";
string s2 = "     ";
string s3 = "   Hello,World  ";

cout << LengthOfLastWord(s) << endl;
cout << LengthOfLastWord(s2) << endl;
cout << LengthOfLastWord(s3) << endl;

system("pause");

return 0;
}

测试：