C++循环语句使用（while for do while）及break continue goto的使用

#include<iostream>
using namespace std;
int main() {
  int sum = 0, i = 1, sum1 = 0;
  /*
  while (i <= 10) {
    sum = sum + i;
    i += 1;//要有计数器 即改变条件表达式的语句 不然会成为死循环
  }
  */
  do {//先do再while判断 while后面要有分号
    sum1 = sum1 + i;
    i += 1;
  } while (i <= 10);
  int sum2 = 0, j = 0;
  for (j = 1; j <= 10; j++) {
    sum2 = sum2 + j;
    int n;
    cin >> n;
    if (n < 0)
      break;
  }
  cout << sum << endl;;
  cout << sum1 << endl;;
  cout << sum2 << endl;;
}