Thread: interpretation

Code:

        #include<stdio.h>

        #define ROWS 3
        #define COLUMNS 4

        void sub1 ( int z[][COLUMNS]);

		void main()


		{
		   int a,b;
		   static int z[ROWS][COLUMNS] = {1,2,3,4,5,6,7,8,9,10,11,12};

		   sub1(z);

		  
		    for(a=0;a<ROWS; ++a)

			{
			      for(b=0;b <COLUMNS; ++b)

				  printf("%d\n", z[a][b]);
			}

		   
		}

		void sub1( int x[][COLUMNS])

		{
		 
			
		    int a,b;
		    for(a=0;a<ROWS; ++a)

			 for(b=0; b<COLUMNS; ++b)

				 if((x[a][b] % 2)==1) 
					 
			       x[a][b]--;

				 return;

		}

the program is correct . what is the meaning of x[a][b]-- here , specially -- sign ?