Quantum Computing – The Next Tech Revolution Technology has evolved rapidly over the last few decades—from bulky mainframe computers to powerful smartphones in our pockets. Yet, despite these advances, traditional computers are approaching their physical limits. This is where quantum computing enters the scene, promising to revolutionize the way we process information and solve complex problems. What Is Quantum Computing? Quantum computing is a new paradigm of computing that uses the principles of quantum mechanics, a branch of physics that explains how matter and energy behave at the smallest scales. Unlike classical computers, which use bits that represent either 0 or 1, quantum computers use qubits. Qubits can exist in multiple states simultaneously, thanks to a property called superposition. Additionally, qubits can be interconnected through entanglement, allowing them to share information instantaneously. These unique properties give quantum computers immense computational power....
Pointer to Pointers
In C, you can also use pointers that point to pointers. The pointers in turn point to data or even to other pointers. To declare pointers to pointers, just add an asterisk * for each level of reference.
For example, consider the following code:
int x=10;
int *px, **ppx;
px = &x;
ppx = &px;
Let us assume, the memory locations of these variables are as shown in Fig.above
Now if we write,
printf("\n %d", **ppx);
Then, it would print 10, the value of x.
Drawbacks of Pointers
Although pointers are very useful in C, they are not free from limitations. If used incorrectly, pointers can lead to bugs that are difficult to unearth. For example, if you use a pointer to read a memory location but that pointer is pointing to an incorrect location, then you may end up reading
a wrong value. An erroneous input always leads to an erroneous output. Thus however efficient your program code may be, the output will always be disastrous. Same is the case when writing a value to a particular memory location.
Let us try to find some common errors when using pointers.
int x, *px;
x=10;
*px = 20;
Error: Un-initialized pointer. px is pointing to an unknown memory location. Hence it willoverwrite that location’s contents and store 20 in it.
int x, *px;
x=10;
px = x;
Error: It should be px = &x;
int x=10, y=20, *px, *py;
px = &x, py = &y;
if(px<py)
printf("\n x is less than y");
else
printf("\n y is less than x");
Error: It should be if(*px< *py)