Using return codes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a return code in C programming?

A return code is an integer value that a function returns to indicate success or failure of its execution. It helps the calling code understand what happened inside the function.

beginner

Why do we use return codes instead of printing error messages directly inside functions?

Using return codes lets the calling function decide how to handle errors, making the program more flexible and easier to maintain. It separates error detection from error handling.

beginner

What does a return code of 0 usually mean in C programs?

A return code of 0 usually means the function or program completed successfully without errors.

beginner

How can you check a function's return code in C?

You can store the return value in a variable and use an if statement to check it. For example:<br>

int result = myFunction();
if (result != 0) {
  // handle error
}

beginner

Give an example of a simple C function that uses return codes to indicate success or failure.

int divide(int a, int b, int *result) {
  if (b == 0) return -1; // error: division by zero
  *result = a / b;
  return 0; // success
}

What does a return code of 0 usually indicate in C?

A Unknown

B Failure

C Warning

D Success

In C, a return code of 0 typically means the function or program ran successfully without errors.

How should a calling function handle a non-zero return code?

A Ignore it

B Treat it as an error and handle accordingly

C Always print a success message

D Restart the program automatically

A non-zero return code usually signals an error, so the calling function should handle it properly.

Which of these is a good reason to use return codes?

A To avoid writing functions

B To make the program run faster

C To separate error detection from error handling

D To print messages automatically

Return codes help separate detecting errors from deciding what to do about them.

What type of value is a return code in C?

A int

B float

C char

D string

Return codes are usually integers (int) in C.

If a function returns -1 as a return code, what does it usually mean?

A Error or failure

B No operation

C Success

D Function is still running

Negative return codes like -1 often indicate an error or failure.

Explain what return codes are and why they are useful in C programming.

Think about how functions tell the rest of the program if they worked or not.

Describe how you would check and handle a return code from a function in C.

Consider a simple if condition after calling a function.