static_cast Casting Operator Explained With Simple Example

This is the simplest type casting operator available in C++. The “static_cast” operator performs a normal cast. This casting operator is basically a substitute for normal casting operator. “static_cast” operator doesn’t do any runtime checks. Hence programmer should consider whether casting is applicable or not.

Normal syntax to do static_cast is as follows:

static_cast <target-type> (expr)

target-type is the target of the cast whereas expr is being cast into the new target-type.

Important Points

• This is the simplest casting operator which is basically a substitute of normal casting.
• This operator doesn’t perform any run time checks.
• This cast operator simply performs a non-polymorphic cast.
• This cast operator throws compile time error if casting is not possible.

Let’s have a look at the sample program to understand static_cast operator functionality.

#include <iostream>

int main ()
{
    int i = 70;
    cout << "Initial value: " << i << " After casting as char: " << static_cast <char> (i) << endl;
}

Let’s analyze the output of above program.

Initial value: 70 After casting as char: F

Difference between normal cast and static_cast

Normal cast doesn’t check the viability of casting being applied on a variable. However, static_cast check the viability of cast being applied on a variable. Hence it throws compile time error in case type casting is incompatible.

Let’s have a look at the example to understand it better.

void fun ()
{
    int i = 70;
    char *x = (char *)&i; /* No compile error */
    /* Below line will throw compile error */
    cout << "Initial value: " << i << " After casting as char: " << static_cast <char *> (i) << endl;
}

If above code is compiled then it will throw following error.

casting_operator.cpp: In function ‘void fun()’:
casting_operator.cpp:86:89: error: invalid static_cast from type ‘int’ to type ‘char*’
   6 |  cout << "Initial value: " << i << " After casting as char: " << static_cast <char *> (i) << endl;