The field width determines the minimum number of character positions used to display a value. If the value occupies fewer characters than the specified width, additional spaces are added to align the output.

The std::setw() manipulator, provided by the <iomanip> library, sets the field width for the next output operation only. It is commonly used to create neatly aligned tables and formatted reports.

Source Code #

#include <iostream>
#include <iomanip>

int main()
{
    std::cout << std::setw(10) << "Name"
              << std::setw(8) << "Age" << '\n';

    std::cout << std::setw(10) << "Alice"
              << std::setw(8) << 24 << '\n';

    std::cout << std::setw(10) << "Bob"
              << std::setw(8) << 31 << '\n';

    return 0;
}

Output #

      Name     Age
     Alice      24
       Bob      31

Explanation #

• #include <iomanip> includes the header that provides formatting manipulators.
• std::setw(width) specifies the minimum field width for the next output value.
• If the output value is shorter than the specified width, leading spaces are added by default.
• If the output value is longer than the specified width, the entire value is printed without truncation.
• The effect of std::setw() applies only to the next insertion operation and must be specified again for subsequent values.
• Field width is commonly used to align columns in tabular output.
• std::cout displays the formatted data on the console.
• return 0; terminates the program successfully.