#include using namespace std; const int N = 110; int a[N], idx; // 1234000 int main() { int n; cin >> n; if (n == 0) { cout << 0 << endl; exit(0); } if (n < 0) { cout << "-"; n = -n; } while (n) { a[++idx] = n % 10; //由后到前 4 3 2 1 --> a[1]=4 a[2]=3 n /= 10; } bool flag = false; //是不是已经遇到过一个非零数字 for (int i = 1; i <= idx; i++) { if (a[i] != 0) flag = true; if (a[i] == 0) { if (flag) cout << 0; } else cout << a[i]; } return 0; }