subplot(m,n,p)command helps to plot multiple graphs on a single graphic window. It breaks the window into an m-by-n matrix of sub-windows and selects the p-th sub-window for drawing the current plot.

For e.g., subplot(2,2,1) divides the window into 4 parts (2 rows and 2 columns)  Third number indicates the number of the plot, here we have selected the first plot.

Similarly, subplot(3,2,2) will divide the graphic window in 6 parts (3 rows and 2 columns) and third number which is '2' indicates the number of the plot.