CareerCup

Check for the NULL after every malloc and free the memory at the end of the program (though its not required in this case but its generally a good practice to do that).

The problem with the code is that a pointer is having the address of the memory location having the string.so change it it is not authorized ..which we try to do in concatenation.strcat().

i think there is no error

i think there is no error

not judge whether malloc succeeds.

I am concerned here about the operation strcat.
P is a character pointer, and using malloc it got a space for 25 characters.
Similar is the case with Q.
Both have some values copied in their memory locations.
So, for P, value will be like amazon_ _ _ _ _ _ _25thlocation
For Q, value will be like hyd_ _ _ _ _ _25thlocation.
When we concat them, will the empty spaces in P and Q be trimmed off or not?

all is fine but one can say a missing free mmory part but i think that should be not a big issue here

i too agree with geeks and ardent...

As such, nothing is wrong with the program, unless you want to implement coding best-practices:

1. You should check return of malloc - whether it has returned NULL or not.
2. Use strncpy, and strncat; Although this is not be an absolute requirement as long as malloc size and strings are hard-coded.
3. main should return int, and should also return an exit value.
4. p and q should be initialized to NULL.

i compiled
no problem
it prints amazonhyd

dont we have to mention the (size of char) fo rmalloc? Usually if you have malloc(i) and i is integer it works.. here it is char.. so the value is 1 byte and therefore working properly..

i think no problem here it works fine

i think after strcat it should be assigned to a varible and then print

Printf uses character pointer and prints it until it finds a null character. As malloc returns a memory with garbage data printf may print some garbage data after two strings 'amazon' and 'hyd'.so we need to either initialise the memory allocated with malloc to null or allocate the memory using calloc.

there is no error. An error would have occurred, if no memory is allocated to the char*. As the compiler doesn't know the termination length, it cannot concatenate or copy (strcat n strcpy do not work ) and throws a segmentation fault.

no error

no error

The issue seems to be the fact that strcpy() and strcat() do not check how much memory is actually allocated to the addresses (similar to C doing no bound checking on array). For example, even if one does this, it still appears to work:

char *p = (char *) malloc (0);
char *q = (char *) malloc (0);

maybe you didn't free the memory!!

malloc does not return any address after allocation.
Thus assignment of malloc to a char pointer is wrong