Final Answer:
The symbol used to signify that a parameter is a pointer is an asterisk (*).
Step-by-step explanation:
In programming languages, particularly in C and C++, the asterisk (*) symbol is used to denote pointers. A pointer is a variable that stores the memory address of another variable. When defining a function that takes a pointer as a parameter, the asterisk is used in the function signature to indicate that the parameter is a pointer. For example, in C++, if we have a function `void foo(int* ptr)`, the asterisk before 'ptr' indicates that 'ptr' is a pointer to an integer.
This notation helps in distinguishing between regular variables and pointers in function declarations. When a function takes a pointer as a parameter, it means it can directly manipulate the data at the memory location pointed to by that pointer. Understanding this distinction is crucial for proper memory management and efficient use of pointers in programming.
To illustrate, consider the following code snippet:
```cpp
#include <iostream>
void square(int* ptr) {
*ptr = (*ptr) * (*ptr);
}
int main() {
int num = 5;
square(&num);
std::cout << "Squared value: " << num << std::endl;
return 0;
}
```
In this example, the `square` function takes a pointer to an integer as a parameter, and the asterisk is used to access the value at the memory location pointed to by 'ptr'. The result is that the 'num' variable is squared in place.