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C-style formatting

As explained in 100 C++ Mistakes and How to Avoid Them

C-style formatting is output construction based on a format string containing conversion directives and corresponding arguments.

C-style formatting builds output from readable text, conversion directives, and a matching list of arguments. The approach is compact, but mismatched types, placeholders, or argument counts can compile without warnings and produce undefined behavior. section 4.3

A maintenance-sensitive formatting call

A Student record can be printed with sprintf using %s, %d, and %.2f for the name, age, and GPA. The code must convert std::string with c_str() and preserve both placeholder types and argument order; swapping either can compile cleanly while making behavior surprising. section 4.3

Prefer the least cumbersome compatible alternative:

  • Use stringstream for clean operator<< output, while recognizing that detailed padding and conversion can become awkward. section 4.3

How 100 C++ Mistakes and How to Avoid Them covers it

How deep it goes
Explains directives, argument matching, and alternatives through listings, but stops short of detailed format-specifier coverage.
Examples
Uses a Student record containing a name, age, and GPA to compare sprintf, stringstream, and std::format.
What it assumes
Assumes basic C++ values and strings while introducing conversion directives and their relationship to argument types.
What you can do after
Apply it via compatible formatting techniques while checking directive types, argument counts, and argument order.
How it connects
Connects format specifiers with undefined behavior, std::string, stringstream, operator<<, and std::format.
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