C++ numbers are output by the specified number of digits

Reprinted from https://blog.csdn.net/zy122121cs/article/details/52094352

Here we discuss how C++ outputs the data according to the specified number of digits. For example, all the data printed on the screen are output according to 4 digits, and the front is filled with 0 if it is not enough. Two output controls of C++ are used here, setw (number of digits), and setfill (specified characters).

Without further ado, see the code below:

    #include <iostream>  
    #include <iomanip>//Be sure to include this c++ header file, very important  
      
    using namespace std;  
      
    intmain()  
    {  
        int test[4] = { 1, 12, 123, 1234 };  
        for (int i = 0; i < 4; ++i)  
        {  
            cout << setw(4) << setfill('0') << test[i] << " ";  
        }  
        cout << endl << endl;  
        return 0;  
    }