string以空格分割字符串

用istringstream 分割

#include<sstream> //istream

string text = "aaa bb ccc d";
istringstream is(text);
string word;
while (is >> word) {
    cout<<word<<endl;
}

输出结果:

aaa
bb
ccc
d

还可以直接调库：

istringstream iss{text};
vector<string> words(istream_iterator<string>(iss),{});
for (auto w:words) { 
    cout<<w<<endl;
}