#include<iostream> #include<iomanip> using namespace std; int main() { cout << "系统默认是右对齐" << endl; cout << setw(8) << 1.23 << endl; cout << setw(8) << 1.23456 << endl; cout << "设置left后,左对齐" << endl; cout << left; cout << setw(8) << 1.23 << endl; cout << setw(8) << 1.23456 << endl; return 0; }