#include <stdio.h>
#include <stdlib.h>

typedef unsigned short int UINT16; 

UINT16  sbox_table[16] = {0xE, 0x4, 0xD, 0x1, 0x2, 0xF, 0xB, 0x8, 0x3, 0xA, 0x6, 0xC, 0x5, 0x9, 0x0, 0x7};

int lin_appr_table[16][16];


void construct_lin_appr_table()
{
	UINT16 i, j, k;

	UINT16 X, Y, x;
	UINT16 X_xor, Y_xor;
	int counter;

	for (i=0 ; i<16 ; i++)//sbox input
	{
		
		for (j=0 ; j<16 ; j++)//sbox output
		{
			X=i;
			Y=j;
			
			counter=0;
			for (k=0;k<16;k++)
			{
              X_xor=X&k;
              Y_xor=Y&sbox_table[k];
              
              if(X_xor^Y_xor==0) counter++;
              
             
            }
			
			lin_appr_table[i][j]=counter-8;
			
            //Tabloyu oluşturan kodu yazın

		}

	}

    //Tabloyu ekrana basan kodu yazın
    
    
	for (i=0 ; i<16 ; i++)//sbox input
	{
		for (j=0 ; j<16 ; j++)//sbox output
		{
			printf("% d ", lin_appr_table[i][j]);
		}
		printf("\n");
	}

}



int main()
{
	//construct linear approximation table
	construct_lin_appr_table();
	
	getch();
	return 0;
}