What's the mistake i'v did in this?

Code:

`#include<iostream.h>`

#include<stdio.h>

#include<conio.h>

int i,j;

int func1(int x,int y,int z);

int func2(int x,int y);

void main()

{

clrscr();

struct

{

int a;

int b;

}s1[3][3],s2[3][3],s3[3][3],s4[3][3];

for(int i=0;i<=3;i++)

{

for(int j=0;j<=3;j++)

{

cin>>s1[i][j].a;

}

}

for(i=0;i<=3;i++)

{

for(int j=0;j<=3;j++)

{

cin>>s1[i][j].b;

}

}

for(i=0;i<=3;i++)

{

for(int j=0;j<=3;j++)

{

s1[i][j]=s2[i][j];

}

}

for(i=0;i<=3;i++)

{

for(int j=0;j<=3;j++)

{

cout<<func1(s2[i][j].a,s2[i][j].b,s3[i][j].a);

}

}

getch();

}

int func1(int x[3][3],int y[3][3],int z[3][3])

{

for(i=0;i<=3;i++)

{

for(j=0;j<=3;j++)

{

z[i][j]=x[i][j]+y[i][j];

}

}

return z[i][j];

}

//int func2(int x,int y)

//{

// return x*y;

//}