Transfer of control bypasses initialization

Hi all,

i have a switch command. and in case the user enters the command 's' (save), i create an output file, and save the data..
but then a compile error was given as "transfer of control bypasses initialization of:"

Code:

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Code:

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case 's':
            ofstream output_file;
            output_file.open(filename);
                        .... some code....
            output_file.close();
            break;
case 'x':
            break;
        }

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what is the problem here, i need the output file only in this case, why is the compiler complaining and what is the solution ?

thanks

The output_file variable is still in scope at case 'x', but since the variable wouldn't be properly initialized if case 'x' is taken, the compiler complains about that. A simple fix is to put braces around the "body" of case 's', like this:

Code:

---

case 's':
{
            ofstream output_file;
            output_file.open(filename);
                        .... some code....
            output_file.close();
            break;
}
case 'x':
            break;
        }

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I would even rewrite it to something like this which also limits the scope of output_file:

Code:

---

case 's':
    if (ofstream output_file(filename)) {
        .... some code ....
    }
    break;
case 'x':
    break;

---

Or stick the code in a function.

Thank you guys, it works,
although i thought, the compiler would see that i am not using output_file in case 'x' here und hence would not complain

Quote:

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Originally Posted by christop

I would even rewrite it to something like this which also limits the scope of output_file:

Code:

---

case 's':
    if (ofstream output_file(filename)) {
        .... some code ....
    }
    break;
case 'x':
    break;

---

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You may need to use uniform initialisation syntax to get that to compile.

Quote:

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Originally Posted by laserlight

You may need to use uniform initialisation syntax to get that to compile.

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Ah! So you do:

Code:

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case 's':
    if (ofstream output_file{filename}) {
        .... some code ....
    }
    break;
case 'x':
    break;

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(And I should've mentioned that this syntax requires C++11 or later, I believe, but that's already 9 years old at this point.)