wiringPi works only with pin 7

Question

I have this simple code on Raspberry B+.

#include <wiringPi.h>
#include <stdio.h>

int main (int argc, char** argv)
{
  int pin;
  if (argc <2) 
     pin = 7;
  else
     pin = atoi(argv[1]);
  printf("Raspberry Pi wiringPi blink test\n");

  if (wiringPiSetup() == -1)
    return 1;

  pinMode(pin, OUTPUT);

  for (;;){
    printf("LED On\n");
    digitalWrite(pin, 1);
    delay(250);
    printf("LED Off\n");
    digitalWrite(pin, 0);
    delay(250);
  }

  return 0;
}

I want to blink a LED connected to a certain pin. But for some reason the led is blinking only when connected to pin 7. (I have not tried all other pins though, just 8,31,32,33); when I try the command gpio -g 6 write 1 (which is for pin 31) the LED glows... What is wrong with the code?

Answer 1

I figured out!

The wiringPi pin numbering is different from R-Pi! Here is a chart for which pin is which.

It was just a coincidence that pin 7 on R-Pi is pin 7 on wiringPi as well.