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：