Computer Fundamental BEE2-AB
Lab practice 11th January 2011
Q. Write program
During the program execution when we ask memory from the system, it is
good practices to check whether memory is successfully allocated or not. It is
also good practice, in case you return memory back to the system, to check
that you are returning proper memory and not NULL. To make your program
more efficient write two rapper functions for already available malloc and free
as describe below. (rapper function uses original function but add more
feature to it).
a Write a function to gets memory from the system and has int as parameter,
which tells how many bytes to get from the system and return a void pointer to
newly, allocated memory. The most important feature of this function is in
case memory is not available or system fails to allocate memory it should
display an appropriate error message i.e. “Memory not available” and should
exit the program.
b Write a function to free memory allocated by the system and has void
pointer as parameter, which tells location of the memory to be freed and
return an int with value 0 in case of memory is returned, 1 in case it is not
possible. The most important feature of this function is to identify if user of this
function has mistakenly send in the pointer that is pointing to NULL.
Q2. Explain what does the following code do.
1 // Ex. 8.21: ex08_21.cpp
2 // What does this program do?
3 #include <stdio.h>
4 #include <stdlib.h>
5
6
7
8 void mystery1( char *, const char * ); // prototype
9
10 int main()
11 {
12 char *string1;
13 char *string2;
14
15 printf("Enter two strings: ");
16 scanf("%d,%d",&string1,&string2);
17 mystery1 (string1, string2);
18 printf("%s",string1);
19 return 0; // indicates successful termination
20 } // end main
21
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