v0.40: Create exercises. Challenge the community.

flip_case

Your mission

Write a program that takes a single string argument and prints it with every letter's case inverted, followed by a newline.

See it in action

./flip_case "gcc Yelled Back" | cat -e

Expected result

GCC yELLED bACK$

Your checklist

For your own tracking. Tests grade your code.

Each lowercase letter in the input must become its uppercase equivalent.
Each uppercase letter in the input must become its lowercase equivalent.
Any character that is not a letter passes through unchanged.
End the output with a newline.
If the program does not receive exactly one argument (argc must be 2), print wrong number of arguments followed by a newline.

More examples

./flip_case "Hello, World!" | cat -e

Expected result

hELLO, wORLD!$

./flip_case | cat -e

Expected result

wrong number of arguments$

Constraints

Expected files

flip_case.c

Allowed functions

write

flip_case

Transforming text

Your mission

Write a program that takes a single string argument and prints it with every letter's case inverted, followed by a newline.

See it in action

./flip_case "gcc Yelled Back" | cat -e

Expected result

GCC yELLED bACK$

Your checklist

For your own tracking. Tests grade your code.

Each lowercase letter in the input must become its uppercase equivalent.
Each uppercase letter in the input must become its lowercase equivalent.
Any character that is not a letter passes through unchanged.
End the output with a newline.
If the program does not receive exactly one argument (argc must be 2), print wrong number of arguments followed by a newline.

More examples

./flip_case "Hello, World!" | cat -e

Expected result

hELLO, wORLD!$

./flip_case | cat -e

Expected result

wrong number of arguments$

Constraints

Expected files

flip_case.c

Allowed functions

write

Tests

Run the tests to grade your code

Build your code, then check each test here. Open a result to inspect its output.

Build

01No argumentsWaiting

02Mixed case with dev-culture stringWaiting

03Letters and punctuationWaiting

04Alphanumeric mixWaiting

05Empty stringWaiting

06All uppercase inputWaiting

07All lowercase inputWaiting

flip_case

Your mission

Write a program that takes a single string argument and prints it with every letter's case inverted, followed by a newline.

See it in action

./flip_case "gcc Yelled Back" | cat -e

Expected result

GCC yELLED bACK$

Your checklist

For your own tracking. Tests grade your code.

Each lowercase letter in the input must become its uppercase equivalent.
Each uppercase letter in the input must become its lowercase equivalent.
Any character that is not a letter passes through unchanged.
End the output with a newline.
If the program does not receive exactly one argument (argc must be 2), print wrong number of arguments followed by a newline.

More examples

./flip_case "Hello, World!" | cat -e

Expected result

hELLO, wORLD!$

./flip_case | cat -e

Expected result

wrong number of arguments$

Constraints

Expected files

flip_case.c

Allowed functions

write

v0.40: Create exercises. Challenge the community.

Meet Studio →

flip_case

Transforming text

Your mission

Write a program that takes a single string argument and prints it with every letter's case inverted, followed by a newline.

See it in action

./flip_case "gcc Yelled Back" | cat -e

Expected result

GCC yELLED bACK$

Your checklist

For your own tracking. Tests grade your code.

Each lowercase letter in the input must become its uppercase equivalent.
Each uppercase letter in the input must become its lowercase equivalent.
Any character that is not a letter passes through unchanged.
End the output with a newline.
If the program does not receive exactly one argument (argc must be 2), print wrong number of arguments followed by a newline.

More examples

./flip_case "Hello, World!" | cat -e

Expected result

hELLO, wORLD!$

./flip_case | cat -e

Expected result

wrong number of arguments$

Constraints

Expected files

flip_case.c

Allowed functions

write

Tests

Run the tests to grade your code

Build your code, then check each test here. Open a result to inspect its output.

Build

01No argumentsWaiting

02Mixed case with dev-culture stringWaiting

03Letters and punctuationWaiting

04Alphanumeric mixWaiting

05Empty stringWaiting

06All uppercase inputWaiting

07All lowercase inputWaiting