#!/bin/sh
# This is a shar archive.
# The rest of this file is a shell script which will extract:
#
# 6_16.h 6_16h0.h 6_16h1.h 6_16h10.h 6_16h11.h 6_16h12.h 6_16h13.h 6_16h14.h 6_16h15.h 6_16h16.h 6_16h17.h 6_16h18.h 6_16h19.h 6_16h2.h 6_16h20.h 6_16h21.h 6_16h22.h 6_16h23.h 6_16h24.h 6_16h25.h 6_16h26.h 6_16h27.h 6_16h28.h 6_16h3.h 6_16h4.h 6_16h5.h 6_16h6.h 6_16h7.h 6_16h8.h 6_16h9.h makefile mat4.h mat4all.c tst.c tst.cmp
#
# To extract the files from this shell archive file simply
# create a directory for this file, move the archive file
# to it and enter the command
#
#	sh filename
# 
# The files will be extracted automatically.
# Note: Do not use csh.
#
# Archive created: Mon Jul 30 23:06:47 EDT 1990
#
echo x - 6_16.h
sed 's/^X//' > 6_16.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
/*
	vector of four vec4's
	Exercise 6.16
*/
#ifndef MAT4_H
#define MAT4_H

# include <stream.h>
# include <vec4.h>

overload gauss;

#include "6_16h0.h"			  // EXPAND class, ~mat4()
    mat4();				  // mat4 x;
					  // new mat4;
    mat4(mat4& a);			  // mat4 x = y;
    mat4(vec4 a);			  // mat4 x = v;
    mat4(float a);			  // mat4 x = 5.;
    mat4(int a);			  // mat4 x = 5;
    mat4(vec4 a, vec4 b, vec4 c, vec4 d); // mat4 x(a, b, c, d);

    mat4 operator=(mat4 a);		  // x = y;
    mat4 operator=(vec4 a);		  // x = v;
    mat4 operator=(float a);		  // x = 35.;
    mat4 operator=(int a);		  // x = 35;

    vec4& operator[](int i);		  // v = m[i]

    friend int operator==(mat4 a, mat4 b);// b = m == n
    friend int operator!=(mat4 a, mat4 b);// b = m != n

    friend mat4 operator+(mat4 a, mat4 b);// b = m + n
    friend mat4 operator-(mat4 a, mat4 b);// b = m - n
    friend mat4 operator+(mat4 a);	  // b = +m
    friend mat4 operator-(mat4 a);	  // b = -m
    mat4 operator+=(mat4 a);		  // m += n
    mat4 operator-=(mat4 a);		  // m -= n
    mat4 operator*=(mat4 a);		  // m *= n

    // matrix multiplication defined in terms
    // of dot products of the vectors
    friend mat4 operator*(mat4 a, mat4 b);
    // multiply the row-vector times the matrix
    friend vec4 operator*(vec4 a, mat4 b);
    // multiply the matrix times the column-vector
    friend vec4 operator*(mat4 a, vec4 b);
    friend mat4 operator*(mat4 a, float b);// b = m * 5.
    friend mat4 operator*(mat4 a, int b);  // b = m * 5

    // Do gaussian elimination on two matrices
    // Return 1 if succeeded, 0 if singular
    friend int gauss(mat4& a, mat4& b);

    // do gaussian elimination on a matrix & vector
    friend int gauss(mat4& a, vec4& b);

					  // cout << m
    friend ostream& operator<< (ostream& out, mat4 a);
};
#endif /* MAT4_H */
!EOF!
ls -l 6_16.h
echo x - 6_16h0.h
sed 's/^X//' > 6_16h0.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
class mat4
{
    vec4 v[4];

public:
    ~mat4() {}		// delete mat4;
    // ...
!EOF!
ls -l 6_16h0.h
echo x - 6_16h1.h
sed 's/^X//' > 6_16h1.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// mat4 x; or new mat4;
mat4::mat4()
{
    v[0] = 0;
    v[1] = 0;
    v[2] = 0;
    v[3] = 0;
}
!EOF!
ls -l 6_16h1.h
echo x - 6_16h10.h
sed 's/^X//' > 6_16h10.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// x = 35;
mat4 mat4::operator=(int a)
{
    v[0] = v[1] = v[2] = v[3] = a;
    return *this;
}
!EOF!
ls -l 6_16h10.h
echo x - 6_16h11.h
sed 's/^X//' > 6_16h11.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// v = m[i]
vec4& mat4::operator[](int i)
{
    return v[(i > 0) && (i < 4) ? i : 0];
}
!EOF!
ls -l 6_16h11.h
echo x - 6_16h12.h
sed 's/^X//' > 6_16h12.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// b = m == n
int operator==(mat4 a, mat4 b)
{
    int v0 = (a.v[0] == b.v[0]);
    int v1 = (a.v[1] == b.v[1]);
    int v2 = (a.v[2] == b.v[2]);
    int v3 = (a.v[3] == b.v[3]);
    return v0 && v1 && v2 && v3;
}
!EOF!
ls -l 6_16h12.h
echo x - 6_16h13.h
sed 's/^X//' > 6_16h13.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// b = m != n
int operator!=(mat4 a, mat4 b)
{
    int v0 = (a.v[0] != b.v[0]);
    int v1 = (a.v[1] != b.v[1]);
    int v2 = (a.v[2] != b.v[2]);
    int v3 = (a.v[3] != b.v[3]);
    return v0 || v1 || v2 || v3;
}
!EOF!
ls -l 6_16h13.h
echo x - 6_16h14.h
sed 's/^X//' > 6_16h14.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// cout << m
ostream& operator<< (ostream& out, mat4 a)
{
    out << "(";
    out << a.v[0] << ",";
    out << a.v[1] << ",";
    out << a.v[2] << ",";
    out << a.v[3] << ")";
    return out;
}
!EOF!
ls -l 6_16h14.h
echo x - 6_16h15.h
sed 's/^X//' > 6_16h15.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// b = m + n
mat4 operator+(mat4 a, mat4 b)
{
    mat4 ret(a.v[0] + b.v[0],
	a.v[1] + b.v[1],
	a.v[2] + b.v[2],
	a.v[3] + b.v[3]);
    return ret;
}
!EOF!
ls -l 6_16h15.h
echo x - 6_16h16.h
sed 's/^X//' > 6_16h16.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// b = m - n
mat4 operator-(mat4 a, mat4 b)
{
    mat4 ret(a.v[0] - b.v[0],
	a.v[1] - b.v[1],
	a.v[2] - b.v[2],
	a.v[3] - b.v[3]);
    return ret;
}
!EOF!
ls -l 6_16h16.h
echo x - 6_16h17.h
sed 's/^X//' > 6_16h17.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// b = +m
mat4 operator+(mat4 a)
{
    mat4 ret = a;
    return ret;
}

!EOF!
ls -l 6_16h17.h
echo x - 6_16h18.h
sed 's/^X//' > 6_16h18.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// b = -m
mat4 operator-(mat4 a)
{
    mat4 ret(-a.v[0], -a.v[1], -a.v[2], -a.v[3]);
    return ret;
}
!EOF!
ls -l 6_16h18.h
echo x - 6_16h19.h
sed 's/^X//' > 6_16h19.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// matrix multiplication defined in terms
// of dot products of the vectors
mat4 operator*(mat4 a, mat4 b)
{
    vec4 b_c0(b.v[0][0], b.v[1][0],
	      b.v[2][0], b.v[3][0]);
    vec4 b_c1(b.v[0][1], b.v[1][1],
	      b.v[2][1], b.v[3][1]);
    vec4 b_c2(b.v[0][2], b.v[1][2],
	      b.v[2][2], b.v[3][2]);
    vec4 b_c3(b.v[0][3], b.v[1][3],
	      b.v[2][3], b.v[3][3]);
    vec4 r_r0(a.v[0].dot(b_c0), a.v[0].dot(b_c1),
	      a.v[0].dot(b_c2), a.v[0].dot(b_c2));
    vec4 r_r1(a.v[1].dot(b_c0), a.v[1].dot(b_c1),
	      a.v[1].dot(b_c2), a.v[1].dot(b_c2));
    vec4 r_r2(a.v[2].dot(b_c0), a.v[2].dot(b_c1),
	      a.v[2].dot(b_c2), a.v[2].dot(b_c2));
    vec4 r_r3(a.v[3].dot(b_c0), a.v[3].dot(b_c1),
	      a.v[3].dot(b_c2), a.v[3].dot(b_c2));
    mat4 ret(r_r0, r_r1, r_r2, r_r3);
    return ret;
}
!EOF!
ls -l 6_16h19.h
echo x - 6_16h2.h
sed 's/^X//' > 6_16h2.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// mat4 x = y;
mat4::mat4(mat4& a)
{
    v[0] = a.v[0];
    v[1] = a.v[1];
    v[2] = a.v[2];
    v[3] = a.v[3];
}
!EOF!
ls -l 6_16h2.h
echo x - 6_16h20.h
sed 's/^X//' > 6_16h20.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// m += n
mat4 mat4::operator+=(mat4 a)
{
    v[0] += a.v[0];
    v[1] += a.v[1];
    v[2] += a.v[2];
    v[3] += a.v[3];
    return *this;
}
!EOF!
ls -l 6_16h20.h
echo x - 6_16h21.h
sed 's/^X//' > 6_16h21.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// m -= n
mat4 mat4::operator-=(mat4 a)
{
    v[0] -= a.v[0];
    v[1] -= a.v[1];
    v[2] -= a.v[2];
    v[3] -= a.v[3];
    return *this;
}
!EOF!
ls -l 6_16h21.h
echo x - 6_16h22.h
sed 's/^X//' > 6_16h22.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// m *= n
mat4 mat4::operator*=(mat4 a)
{
    vec4 a_c0(a.v[0][0], a.v[1][0],
	      a.v[2][0], a.v[3][0]);
    vec4 a_c1(a.v[0][1], a.v[1][1],
	      a.v[2][1], a.v[3][1]);
    vec4 a_c2(a.v[0][2], a.v[1][2],
	      a.v[2][2], a.v[3][2]);
    vec4 a_c3(a.v[0][3], a.v[1][3],
	      a.v[2][3], a.v[3][3]);
    vec4 r_r0(v[0].dot(a_c0), v[0].dot(a_c1),
	      v[0].dot(a_c2), v[0].dot(a_c2));
    vec4 r_r1(v[1].dot(a_c0), v[1].dot(a_c1),
	      v[1].dot(a_c2), v[1].dot(a_c2));
    vec4 r_r2(v[2].dot(a_c0), v[2].dot(a_c1),
	      v[2].dot(a_c2), v[2].dot(a_c2));
    vec4 r_r3(v[3].dot(a_c0), v[3].dot(a_c1),
	      v[3].dot(a_c2), v[3].dot(a_c2));
    *this = mat4(r_r0, r_r1, r_r2, r_r3);
    return *this;
}
!EOF!
ls -l 6_16h22.h
echo x - 6_16h23.h
sed 's/^X//' > 6_16h23.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// multiply the row-vector times the matrix
vec4 operator*(vec4 a, mat4 b)
{
    vec4 ret(a.dot(b.v[0]), a.dot(b.v[1]),
	     a.dot(b.v[2]), a.dot(b.v[3]));
    return ret;
}
!EOF!
ls -l 6_16h23.h
echo x - 6_16h24.h
sed 's/^X//' > 6_16h24.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// multiply the matrix times the column-vector
vec4 operator*(mat4 a, vec4 b)
{
    vec4 ret(a.v[0].dot(b), a.v[1].dot(b),
	     a.v[2].dot(b), a.v[3].dot(b));
    return ret;
}
!EOF!
ls -l 6_16h24.h
echo x - 6_16h25.h
sed 's/^X//' > 6_16h25.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// b = m * 5.
mat4 operator*(mat4 a, float b)
{
    a.v[0] *= b;
    a.v[1] *= b;
    a.v[2] *= b;
    a.v[3] *= b;
    return a;
}
!EOF!
ls -l 6_16h25.h
echo x - 6_16h26.h
sed 's/^X//' > 6_16h26.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// b = m * 5
mat4 operator*(mat4 a, int b)
{
    a.v[0] *= b;
    a.v[1] *= b;
    a.v[2] *= b;
    a.v[3] *= b;
    return a;
}
!EOF!
ls -l 6_16h26.h
echo x - 6_16h27.h
sed 's/^X//' > 6_16h27.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#include <swap.h>

// Do gaussian elimination on two matrices
// Return 1 if succeeded, 0 if singular
int gauss(mat4& a, mat4& b)
{
    for (int diag = 0; diag < 4; diag++)
	{
	// check for zero diagonal element
	if (a.v[diag][diag] == 0)
	    {
	    // look for non-zero element
	    for (int row = diag + 1; row < 4; row++)
		if (a.v[diag][row] != 0)
		    {
		    // found one, swap into diagonal
		    for (int col = 0; col < 4; col++)
			swap(a.v[col][row],
			     a.v[col][diag]);

		    for (col = 0; col < 4; col++)
			swap(b.v[col][row],
			     b.v[col][diag]);
		    break;
		    }

	    // none available?
	    if (row == 4)
		// return with what we have
		return 0;
	    }

	// reduce each row below
	// the diagonal element
	for (int row = diag + 1; row < 4; row++)
	    {
	    float multiplier = a.v[diag][row] /
			       a.v[diag][diag];

	    // subtracting should give
	    // zero, so just set it
	    for (int col = 0; col < diag; col++)
		a.v[col][row] = 0.0;

	    // reduce the row on the left
	    for ( ; col < 4; col++)
		a.v[col][row] -= a.v[col][0] *
		    multiplier;

	    // reduce the row on the right
	    for (col = 0; col < 4; col++)
		b.v[col][row] -= b.v[col][0] *
		    multiplier;
	    }
	}

    return 1;
}
!EOF!
ls -l 6_16h27.h
echo x - 6_16h28.h
sed 's/^X//' > 6_16h28.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// do gaussian elimination on a matrix & vector
int gauss(mat4& a, vec4& b)
{
    mat4 mb = b;
    int ret = gauss(a, mb);
    b = mb.v[0];
    return ret;
}
!EOF!
ls -l 6_16h28.h
echo x - 6_16h3.h
sed 's/^X//' > 6_16h3.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// mat4 x = v;
mat4::mat4(vec4 a)
{
    v[0] = v[1] = v[2] = v[3] = a;
}
!EOF!
ls -l 6_16h3.h
echo x - 6_16h4.h
sed 's/^X//' > 6_16h4.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// mat4 x = 5.;
mat4::mat4(float a)
{
    v[0] = v[1] = v[2] = v[3] = a;
}
!EOF!
ls -l 6_16h4.h
echo x - 6_16h5.h
sed 's/^X//' > 6_16h5.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// mat4 x = 5;
mat4::mat4(int a)
{
    v[0] = v[1] = v[2] = v[3] = a;
}
!EOF!
ls -l 6_16h5.h
echo x - 6_16h6.h
sed 's/^X//' > 6_16h6.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// mat4 x(a, b, c, d);
mat4::mat4(vec4 a, vec4 b, vec4 c, vec4 d)
{
    v[0] = a;
    v[1] = b;
    v[2] = c;
    v[3] = d;
}
!EOF!
ls -l 6_16h6.h
echo x - 6_16h7.h
sed 's/^X//' > 6_16h7.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// x = y;
mat4 mat4::operator=(mat4 a)
{
    v[0] = a.v[0]; v[1] = a.v[1];
    v[2] = a.v[2]; v[3] = a.v[3];
    return *this;
}
!EOF!
ls -l 6_16h7.h
echo x - 6_16h8.h
sed 's/^X//' > 6_16h8.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// x = v;
mat4 mat4::operator=(vec4 a)
{
    v[0] = v[1] = v[2] = v[3] = a;
    return *this;
}
!EOF!
ls -l 6_16h8.h
echo x - 6_16h9.h
sed 's/^X//' > 6_16h9.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
// x = 35.;
mat4 mat4::operator=(float a)
{
    v[0] = v[1] = v[2] = v[3] = a;
    return *this;
}
!EOF!
ls -l 6_16h9.h
echo x - makefile
sed 's/^X//' > makefile << '!EOF!'
CC= CC -I. -I../../CC
CFLAGS= -I../6.15dir

all: tst

tst: tst.c 6_16.h 6_16h0.h 6_16h1.h 6_16h10.h 6_16h11.h 6_16h12.h 6_16h13.h \
	6_16h14.h 6_16h15.h 6_16h16.h 6_16h17.h 6_16h18.h 6_16h19.h 6_16h2.h 6_16h20.h \
	6_16h21.h 6_16h22.h 6_16h23.h 6_16h24.h 6_16h25.h 6_16h26.h 6_16h27.h 6_16h28.h \
	6_16h3.h 6_16h4.h 6_16h5.h 6_16h6.h 6_16h7.h 6_16h8.h 6_16h9.h mat4.h
	$(CC) $(CFLAGS) tst.c -o tst

CMP= tst.cmp
OUT= tst.out

tst.out: tst ;	tst > tst.out

test: all $(OUT) $(CMP)
	cmp tst.out tst.cmp
	echo tests done
!EOF!
ls -l makefile
echo x - mat4.h
sed 's/^X//' > mat4.h << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#include "6_16.h"
!EOF!
ls -l mat4.h
echo x - mat4all.c
sed 's/^X//' > mat4all.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#include "6_16h1.h"
#include "6_16h2.h"
#include "6_16h3.h"
#include "6_16h4.h"
#include "6_16h5.h"
#include "6_16h6.h"
#include "6_16h7.h"
#include "6_16h8.h"
#include "6_16h9.h"
#include "6_16h10.h"
#include "6_16h11.h"
#include "6_16h12.h"
#include "6_16h13.h"
#include "6_16h14.h"
#include "6_16h15.h"
#include "6_16h16.h"
#include "6_16h17.h"
#include "6_16h18.h"
#include "6_16h19.h"
#include "6_16h20.h"
#include "6_16h21.h"
#include "6_16h22.h"
#include "6_16h23.h"
#include "6_16h24.h"
#include "6_16h25.h"
#include "6_16h26.h"
#include "6_16h27.h"
#include "6_16h28.h"
!EOF!
ls -l mat4all.c
echo x - tst.c
sed 's/^X//' > tst.c << '!EOF!'
/* Copyright (c) 1990 by AT&T Bell Telephone Laboratories, Incorporated. */
/* The C++ Answer Book */
/* Tony Hansen */
/* All rights reserved. */
#include "mat4.h"
#include "mat4all.c"
#include "vec4all.h"

main()
{
    mat4 a;
    cout << "a=\n" << a << "\n";
    mat4 b = 5;
    cout << "b=\n" << b << "\n";
    mat4 c = (float) 6.;
    cout << "c=\n" << c << "\n";
    mat4 d = c;
    cout << "d=\n" << d << "\n";
    vec4 v1(1., 2., 3., 4.);
    cout << "v1=\n" << v1 << "\n";
    mat4 e = v1;
    cout << "e=\n" << e << "\n";
    cout << "e[1]=\n" << e[1] << "\n";
    cout << "e[1][3]=\n" << e[1][3] << "\n";
    mat4 f(v1,v1,v1,v1);
    cout << "f=\n" << f << "\n";
    a = b;
    cout << "a=\n" << a << "\n";
    a = v1;
    cout << "a=\n" << a << "\n";
    a = 5;
    cout << "a=\n" << a << "\n";
    cout << "a == b ? " << (a == b) << "\n";
    cout << "a != b ? " << (a != b) << "\n";
    cout << "a == c ? " << (a == c) << "\n";
    cout << "a != c ? " << (a != c) << "\n";
    a = (float) 23.5;
    cout << "a=\n" << a << "\n";

    a = b + c;    
    cout << "a=b+c=\n" << a << "\n";
    a = b - c;    
    cout << "a=b-c=\n" << a << "\n";
    a = +b;
    cout << "a= +b=\n" << a << "\n";
    a = -b;
    cout << "a= -b=\n" << a << "\n";
    a += c;
    cout << "a += c=\n" << a << "\n";
    a -= d;
    cout << "a -= d=\n" << a << "\n";
    a *= b;
    cout << "a *= b=\n" << a << "\n";
    a = b * c;    
    cout << "a=b*c=\n" << a << "\n";
    a = v1 * c;    
    cout << "a=v1*c=\n" << a << "\n";
    a = b * v1;    
    cout << "a=b*v1=\n" << a << "\n";
    b = 0;
    b[1][1] = 1;
    b[2][2] = 1;
    b[3][3] = 1;
    b[4][4] = 1;
    cout << "b=\n" << b << "\n";
    c = a;
    int ret = gauss(a, b);
    cout << "a=\n" << a << "\n";
    cout << "b=\n" << b << "\n";
    cout << "ret=" << ret << "\n";
    a = c;
    v1 = 0;
    ret = gauss(a, v1);
    cout << "a=\n" << a << "\n";
    cout << "v1=\n" << v1 << "\n";
    cout << "ret=" << ret << "\n";
    return 0;
}
!EOF!
ls -l tst.c
echo x - tst.cmp
sed 's/^X//' > tst.cmp << '!EOF!'
a=
((0,0,0,0),(0,0,0,0),(0,0,0,0),(0,0,0,0))
b=
((5,5,5,5),(5,5,5,5),(5,5,5,5),(5,5,5,5))
c=
((6,6,6,6),(6,6,6,6),(6,6,6,6),(6,6,6,6))
d=
((6,6,6,6),(6,6,6,6),(6,6,6,6),(6,6,6,6))
v1=
(1,2,3,4)
e=
((1,2,3,4),(1,2,3,4),(1,2,3,4),(1,2,3,4))
e[1]=
(1,2,3,4)
e[1][3]=
4
f=
((1,2,3,4),(1,2,3,4),(1,2,3,4),(1,2,3,4))
a=
((5,5,5,5),(5,5,5,5),(5,5,5,5),(5,5,5,5))
a=
((1,2,3,4),(1,2,3,4),(1,2,3,4),(1,2,3,4))
a=
((5,5,5,5),(5,5,5,5),(5,5,5,5),(5,5,5,5))
a == b ? 1
a != b ? 0
a == c ? 0
a != c ? 1
a=
((23.5,23.5,23.5,23.5),(23.5,23.5,23.5,23.5),(23.5,23.5,23.5,23.5),(23.5,23.5,23.5,23.5))
a=b+c=
((11,11,11,11),(11,11,11,11),(11,11,11,11),(11,11,11,11))
a=b-c=
((-1,-1,-1,-1),(-1,-1,-1,-1),(-1,-1,-1,-1),(-1,-1,-1,-1))
a= +b=
((5,5,5,5),(5,5,5,5),(5,5,5,5),(5,5,5,5))
a= -b=
((-5,-5,-5,-5),(-5,-5,-5,-5),(-5,-5,-5,-5),(-5,-5,-5,-5))
a += c=
((1,1,1,1),(1,1,1,1),(1,1,1,1),(1,1,1,1))
a -= d=
((-5,-5,-5,-5),(-5,-5,-5,-5),(-5,-5,-5,-5),(-5,-5,-5,-5))
a *= b=
((-100,-100,-100,-100),(-100,-100,-100,-100),(-100,-100,-100,-100),(-100,-100,-100,-100))
a=b*c=
((120,120,120,120),(120,120,120,120),(120,120,120,120),(120,120,120,120))
a=v1*c=
((60,60,60,60),(60,60,60,60),(60,60,60,60),(60,60,60,60))
a=b*v1=
((50,50,50,50),(50,50,50,50),(50,50,50,50),(50,50,50,50))
b=
((1,0,0,0),(0,1,0,0),(0,0,1,0),(0,0,0,1))
a=
((50,0,0,0),(50,0,0,0),(50,0,0,0),(50,0,0,0))
b=
((1,-1,-1,-1),(0,1,0,0),(0,0,1,0),(0,0,0,1))
ret=0
a=
((50,0,0,0),(50,0,0,0),(50,0,0,0),(50,0,0,0))
v1=
(0,0,0,0)
ret=0
!EOF!
ls -l tst.cmp
# The following exit is to ensure that extra garbage 
# after the end of the shar file will be ignored.
exit 0