Question

I need the send and integer to a function and then append that to the end of a constant character.

int main (void)
{
    append(1);
}

int append(int input)
{
    const char P = 'P';

    //This where I want to append 1 to P to create "P1"'
}

Answer 1

No matter what you do, you need to convert the number to a string, otherwise you can’t create a string containing both numbers.

You can actually combine both the concatenation and the int-to-string conversion in one function call: sprintf:

char output[16];
sprintf(output, "P%d", input);