By default, when the field width is greater than the size of the output value, the remaining positions are filled with spaces. C++ allows the fill character to be changed using the std::setfill() manipulator provided by the <iomanip> library.

The fill character remains active for all subsequent output operations until another fill character is specified. It is commonly used when formatting tables, reports, and decorative console output.

Source Code #

#include <iostream>
#include <iomanip>

int main()
{
    std::cout << std::setfill('*');

    std::cout << std::setw(10) << 25 << '\n';
    std::cout << std::setw(10) << 350 << '\n';
    std::cout << std::setw(10) << 7890 << '\n';

    return 0;
}

Output #

********25
*******350
******7890

Explanation #

• #include <iomanip> includes the header that provides stream formatting manipulators.
• std::setfill('*') changes the fill character from the default space to an asterisk (*).
• std::setw(10) specifies that the next output value should occupy a minimum field width of 10 characters.
• If the output value is shorter than the specified field width, the remaining positions are filled with the current fill character.
• Unlike std::setw(), which affects only the next output operation, std::setfill() remains in effect until another fill character is specified.
• The stored values are not modified; only their displayed representation changes.
• std::cout displays the formatted output on the console.
• return 0; terminates the program successfully.