使用了string的find函式和substr函式

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

vector<string> split(string str, string pattern) {
    vector<string> result;
    str += pattern;
    for (int i = 0; i < str.size(); i++) {
        int pos = (int
 
)str.find(pattern, i);
        if (pos != string::npos) {
            result.push_back(str.substr(i, pos - i));
            i = pos + (int)pattern.size() - 1;
        }
    }
    return result;
}

int main() {
    string s = "I have a dream!";
    vector<string> res = split(s, " ");
    return
 
 0;
}