What is returned by the function if the space cannot be allocated by the function malloc(), realloc() and calloc()?

A. strlen() B. strlength() C. stringlen() D. strsize()

A. To print formatted text to the standard output B. To read text from the standard input C. To open a file D. To close a file

A. math.h B. stdlib.h C. cmath.h D. algorithm.h

A. Compares two strings and returns an integer indicating their relationship B. Copies one string to another C. Concatenates two strings D. Searches for a substring