C Programming 09/10

Question 1

What is realloc?

Answer 1

Allows you to change the size of a buffer which was previously malloced.
• void* realloc(void* ptr, int size);

Question 2

What is memcpy?

Answer 2

Copies bytes from one memory area to another area.

• void *memcpy(void *restrict dst, const void *restrict src, size_t n);

Question 3

What is alignment?

Answer 3

Many types have limitations on the memory address they can be placed at, it results in slower performance and wasted memory

Question 4

What is getchar?

Answer 4

Function that gets a single character from stdin
• int getchar(void);
• Returns EOF or an unsigned char

Question 5

What is putchar?

Answer 5

Function that puts a single character to stdout
• int putchar(int c);
• Should provide unsigned char, returns error value

Question 6

What is fopen?

Answer 6

Opens a file and returns a file stream
• FILE *fopen(const char *fname, const char *mode);
• Returns a stream or NULL

Question 7

What are the file modes?

Answer 7

• “r” = Open file for reading
• “w” = Open file for writing
• “a” = Open file for appending at end of file (retain existing data)

Question 8

What is fclose?

Answer 8

Closes file associated with file stream
• int fclose(FILE *fp);
• Returns error value

Question 9

What is fgetc?

Answer 9

Function that gets a single character from a file stream

• int fgetc(FILE *stream);

Question 10

What is fputc?

Answer 10

Function that puts a single character to a file stream

• int fputc(int c, FILE *stream);

Question 11

Why use fgetc/fputc over getchar/putchar?

Answer 11

• fgets/fputs take size parameter so safe
• fgets records \n
• fputs doesn’t put \n