CODEWITHSUNDEEP
c++switch-statementc++17
msc
msc

Reputation: 34658

switch statements in C++

What is the difference between following two code snippets of switch statement?

Which one is better? When can I use both of them?

case 1:

int i = 10;
switch(i)
{
//case
}

case 2:

switch(int i = 10, i)
{
//case
}

In second case, C++17 permitted to initialize variables inside the switch statement.

Upvotes: 1

Views: 226

Answers (2)

Jarod42
Jarod42

Reputation: 218228

switch (int i = 42; i) is C++17 and would restrict the scope of i to the switch, it would be mostly equivalent to:

// Code before switch
{ // Additional scope
    int i = 42;
    switch (i) {
    // case...
    }
}
// Code after switch

It would also apply to if

if (int i = 42; i == foo()) {
    // Can use i
} else {
    // Can use i
}

Upvotes: 3

bipll
bipll

Reputation: 11940

In the first version i lives past the switch's scope end. You can use it should you need i later. You can use the second version if your compiler knows C++17.

Upvotes: 5

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