snake_fmt

Transforming text16

Objective

Write a program that reads one camelCase identifier from the command line and prints it reformatted as snake_case.

Steps

Accept exactly one argument after the binary name.
Scan every character of that argument: whenever an uppercase letter is found, emit an underscore followed by the lowercase version of that letter.
All other characters are printed unchanged.
Always finish the output with a newline.
If the argument count is not exactly one, print wrong number of arguments followed by a newline and exit.

examples

$ ./snake_fmt "buildReactApp"

build_react_app

$ ./snake_fmt "vibeCodingMetGccToday" | cat -e

vibe_coding_met_gcc_today$

$ ./snake_fmt | cat -e

wrong number of arguments$

Constraints

Expected files

snake_fmt.c

Allowed functions

write

Tests

Run the tests to grade your code

Build

01No arguments

02Empty string

03Three-segment identifier

04Dev-culture phrase

05Too many arguments

06Single lowercase character

snake_fmt

Objective

Write a program that reads one camelCase identifier from the command line and prints it reformatted as snake_case.

Steps

Accept exactly one argument after the binary name.
Scan every character of that argument: whenever an uppercase letter is found, emit an underscore followed by the lowercase version of that letter.
All other characters are printed unchanged.
Always finish the output with a newline.
If the argument count is not exactly one, print wrong number of arguments followed by a newline and exit.

examples

$ ./snake_fmt "buildReactApp"

build_react_app

$ ./snake_fmt "vibeCodingMetGccToday" | cat -e

vibe_coding_met_gcc_today$

$ ./snake_fmt | cat -e

wrong number of arguments$

Constraints

Expected files

snake_fmt.c

Allowed functions

write

snake_fmt

Transforming text16

Objective

Write a program that reads one camelCase identifier from the command line and prints it reformatted as snake_case.

Steps

Accept exactly one argument after the binary name.
Scan every character of that argument: whenever an uppercase letter is found, emit an underscore followed by the lowercase version of that letter.
All other characters are printed unchanged.
Always finish the output with a newline.
If the argument count is not exactly one, print wrong number of arguments followed by a newline and exit.

examples

$ ./snake_fmt "buildReactApp"

build_react_app

$ ./snake_fmt "vibeCodingMetGccToday" | cat -e

vibe_coding_met_gcc_today$

$ ./snake_fmt | cat -e

wrong number of arguments$

Constraints

Expected files

snake_fmt.c

Allowed functions

write

Tests

Run the tests to grade your code

Build

01No arguments

02Empty string

03Three-segment identifier

04Dev-culture phrase

05Too many arguments

06Single lowercase character