Computer Science - Object Oriented Programming Using C++ - Discussion

Discussion Forum : Object Oriented Programming Using C++ - Section 3 (Q.No. 9)
9.
If you assign a default value to any variable in a function prototype's parameter list, then _____
all other parameters in the function prototype must have default values
all parameters to the right of that variable must have default values
all parameters to the left of that variable must have default values
no other parameters in that prototype can have default values
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
3 comments Page 1 of 1.

SABA said:   4 years ago
@All.

If you want to override constructor default values for an object you are instantiating, you must also override.

B. all parameters to the left of that value.

Things to Remember:-

Once we provide a default value for a parameter, all subsequent parameters must also have default values.

For example:

// Invalid
void add(int a, int b = 3, int c, int d);

// Invalid
void add(int a, int b = 3, int c, int d = 4);

// Valid
void add(int a, int c, int b = 3, int d = 4);

Ayesha said:   4 years ago
void printValues(int x, int y=10) // 10 is the default argument, y is now an optional parameter
{
std::cout << "x: " << x << '\n';
std::cout << "y: " << y << '\n';
}

int main()
{
printValues(1); // y will use default argument 10
printValues(3, 4); // y will use user-supplied argument 4
}

This program produces the following output:
x: 1
y: 10
x: 3
y: 4

Eklesh parmar said:   7 years ago
Ex.
int add(int a, int b, int c= 50).
Default argument are declared from righ- hand side.

Call add(10,20)
a=10, b=20 and c=50 is default value.

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