Question

What will be the output of the following C program?

#include
#include
int main() (
int *p;
p = (int *)malloc(20);
// Assume p has address of 1314
free(p);
printf(%u, p);
return 0;
)

a) 1314
b) 0
c) Some random memory address
d) Compiler error

Answer 1

The output of the C program is 1314, as the pointer p still holds the address of the freed memory despite calling free. However, using p after free is called results in a dangling pointer, which is not safe.

Step-by-step explanation:

The output of the given C program will be:

a) 1314

The program allocates memory using malloc, and p is assigned the address of this allocated memory. After the free function is called, p still holds the address it was initially assigned (1314 in this case, as per the assumption made in the question). The printf function then displays the value of p, which is the address of the freed memory. However, note that this is not a good practice; after free is called, p should not be used without being reassigned, as it becomes a dangling pointer.