查找string中单词的个数

#include <iostream>
#include <cctype>
#include <string>
#include <vector>
using namespace std;


int Sum(string s)
{
int num = 0;


for (decltype(s.size()) index = 0; index != s.size(); ++index)
{
if (isspace(s[index]))
{
num++;//最后一位也是空格，但 要是最后不是呢，未考虑
}
}


return num;
}




int main()
{


string a = "This is a Temp huhu and lala";
int num = 0;
string::size_type i = a.size();
if (isspace(a[i-1]))//最后一位是空格
num = Sum(a);
else
{
num = Sum(a) + 1;
}
cout << num << endl;
getchar();
return 0;


}