error: expected identifier or '(' before 'return'|

This error message usually occurs when the compiler encounters a "return" statement outside of a function. In C or C++, the "return" statement can only be used inside a function to return a value. Here is an example of a correct usage of the "return" statement inside a function:

int sum(int a, int b) {
    int result = a + b;
    return result;
}

If you see this error message and you are not trying to use "return" outside of a function, it may be caused by a missing or misplaced identifier or parentheses in your code. Check your code carefully to make sure all identifiers are spelled correctly and all parentheses are correctly matched.