The return value type of 1. function is the content type returned by the function. Note that if there are multiple ways to end a function, there must be multiple returns, such as.
int fun(int x)
{
if(x & gt； 0)
Returns 0;
other
Returns1;
}
2. The transfer relationship of function parameters, some can change the value, some can't change the value, also give an example:
void fun 1(int x，int *y，int & ampz)
{
x = 1；
* y = 1；
z = 1；
}
If the main function has variables inta = b = c = 2; Fun (a & amp； b，c)； , then the values of b and c will change, and the value of a will not change, because:
A does not operate on the contents of the memory space occupied by variable a.
& ampB is the memory address of the incoming variable B, and the fun function directly operates the memory space where the variable B is located, so B will change.
As for c, I don't need to know for the time being, because the formal parameter int &；; C stands for reference, which will be involved in c++. You use C now, so just know that there is such a method for the time being.
3. Just pay attention to the lifetime of variables in the function, which is a bit troublesome. Please read the part about local variables and global variables in the book, which is more detailed.