Declare variable in if statement (ANSI C)

问题

Is there any way to declare variable in if statement (using ANSI C only) ?

Example:

if(int variable = some_function())
{
    return 1;
}

回答1:

No, you cannot do that.

What you can do is create a block just for the if

    {
        int variable;
        variable = some_function();
        if (variable) return 1;
    }
    /* variable is out of scope here */

Note that for this simple case you can call the function as the condition of the if (no need for an extra variable)

if (some_function()) return 1;

来源：https://stackoverflow.com/questions/43643349/declare-variable-in-if-statement-ansi-c