If \( [x] \) denotes the greatest integer less than or equal to \( x \), then the value of the integral \( \displaystyle\int\limits_{-\pi/2}^{\pi/2} \big[[x]-\sin x\big]\,dx \) is equal to:
\( 1 \)
\( -\pi \)
\( \pi \)
\( 0 \)