Neeed Coding and schematic fort a 4 x 4 keypad interfacing with PIC microcontroller

int readkeypad (void)
{
 output_bit (r1, 0);
 output_bit (r2, 0);
 output_bit (r3, 0);
 output_bit (r4, 0);
 output_bit (r1, 1);//activate 1st row and scan for column
 delay_ms(10);
 IF (input (c1)) RETURN 10;
 IF (input (c2)) RETURN 0;
 IF (input (c3)) RETURN 11;
 //IF (input (c4)) RETURN 12;
 output_bit (r1, 0);//Deactivate 1st row
 output_bit (r2, 1);//activate 2nd row and scan for column
 delay_ms(10);
 IF (input (c1)) RETURN 7;
 IF (input (c2)) RETURN 8;
 IF (input (c3)) RETURN 9;
 //IF (input (c4)) RETURN 13;
 output_bit (r2, 0);//Deactivate 2nd row
 output_bit (r3, 1);//activate 3rd row and scan for column
 delay_ms(10);
 IF (input (c1)) RETURN 4;
 IF (input (c2)) RETURN 5;
 IF (input (c3)) RETURN 6;
 IF (input (c4)) RETURN 14;
 output_bit (r3, 0);//Deactivate 3rd row
 output_bit (r4, 1);//activate 4th row and scan for column
 delay_ms(10);
 IF (input (c1)) RETURN 1;
 IF (input (c2)) RETURN 2;
 IF (input (c3)) RETURN 3;
 IF (input (c4)) RETURN 15;
 output_bit (r4, 0);//Deactivate 4th row
 RETURN 255;
}