What are the important notions in C that you did not learn from your teachers? [closed]

Answer 1

The (dangerous) side effects of macros.

Answer 2

Use of const keyword in pointers context:

The difference between following declarations:

 A)   const char* pChar  // pointer to a CONSTANT char
 B)   char* const pChar  // CONSTANT pointer to a char
 C)   const char* const pChar  // Both

So with A:

const char* pChar = 'M';
*pChar = 'S'; // error: you can't modify value pointed by pChar

And with B:

char OneChar = 'M';
char AnotherChar = 'S';
char* const pChar = &OneChar;
pChar = &AnotherChar; // error: you can't modify address of pChar

Answer 3

Use valgrind

Answer 4

Always active warnings. With GCC, use at least -Wall -Wextra -Wstrict-prototypes -Wwrite-strings.

I/O is difficult. scanf() is evil. gets() should never be used.

When you print something which isn't '\n'-terminated, you have to flush stdout if you want to print it immediatly, e.g.

printf("Type something: ");
fflush(stdout);
getchar();

Use const pointers whenever possible. E.g. void foo(const char* p);.

Use size_t for storing sizes.

Litteral strings generally can't be modified, so make them const. E.g. const char* p = "whatever";.

Answer 5

I think that the overall idea seems really good. These are some extra stuff.

1. A debugger is a good friend.
2. Check the boundaries.
3. Make sure that the pointer is actually pointing to something before it is used.
4. Memory management.

Answer 6

Teach them unit testing.