用for循环或者string解决，不会啊，希望有详细代码

bool hasSpace = false;
string result;
for (int i = 0; i < s.length(); i++) {
  if (hasSpace) {
    if (s[i] != ' ') {
      result += s[i[;
      hasSpace = false;
    }
  } else if (not hasSpace) {
    if (s[i] == ' ' {
      hasSpace = true;
    }
    result += s[i];
}