目标：编写一系列用以操纵“字符图像”的类与函数。所谓的“字符图像”，就是一个可打印的矩形字符阵列。
9.6之前的代码：
Picture.h
#include <iostream>
#include <cstring>
using namespace std;
class Picture{
friend ostream& operator<<(ostream&, const Picture&);
public:
Picture(): height(0), width(0), data(0) {}
int max(int m, int n) { return m > n ? m : n; }
void init(int h, int w){
height = h;
width = w;
data = new char[height * width];
}
Picture(const char* const* array, int n){
int w = 0;
int i;
for(i=0; i<n; i++)
w = max(w, strlen(array[i]));
init(n, w);
for(i=0; i<n; i++){
const char* src = array[i];
int len = strlen(src);
int j = 0;
while(j < len){
position(i, j) = src[j];
++j;
}
while(j < width){
position(i, j) = ' ';
++j;
}
}
}
Picture(const Picture& p): height(p.height), width(p.width), data(new char[p.height * p.width]){ copyblock(0, 0, p); }
~Picture() { delete[] data; }
Picture& operator=(const Picture& p);
private:
int height, width;
char *data;
char& position(int row, int col){
return data[row * width + col];
}
char position(int row, int col) const{
return data[row * width + col];
}
void copyblock(int row, int col, const Picture& p){
for(int i=0; i<p.height; ++i){
for(int j=0; j<p.width; ++j)
position(i+row, j+col) = p.position(i, j);
}
}
};
ostream& operator<<(ostream&, const Picture&);
Picture frame(const Picture& p);
Picture operator&(const Picture&, const Picture&);
Picture operator|(const Picture&, const Picture&);
picturecontrol.cpp:
#include <iostream>
#include "Picture.h"
using namespace std;
const char* init[] = {"Paris", "in the", "Spring"};
ostream& operator<<(ostream& o, const Picture& p){
for(int i=0; i<p.height; ++i){
for(int j=0; j<p.width; ++j){
o << p.position(i, j);
}
o << endl;
}
return o;
}
Picture frame(const Picture& p)
{}
Picture operator&(const Picture&, const Picture&)
{}
Picture operator|(const Picture&, const Picture&)
{}
int main(int argc, char const *argv[])
{
Picture p(init, 3);
cout << p << endl;
Picture q = p;
cout << q << endl;
//Picture r = p | q;
//cout << r << endl;
//Picture s = q & r;
//cout << s << endl;
//cout << frame(s) << endl;
return 0;
}
#include <iostream>
#include <cstring>
using namespace std;
class Picture{
friend ostream& operator<<(ostream&, const Picture&);
friend Picture frame(const Picture& p);
friend Picture operator&(const Picture&, const Picture&);
friend Picture operator|(const Picture&, const Picture&);
public:
Picture(): height(0), width(0), data(0) {}
Picture(const char* const* array, int n){
int w = 0;
int i;
for(i=0; i<n; i++)
w = max(w, strlen(array[i]));
init(n, w);
for(i=0; i<n; i++){
const char* src = array[i];
int len = strlen(src);
int j = 0;
while(j < len){
position(i, j) = src[j];
++j;
}
while(j < width){
position(i, j) = ' ';
++j;
}
}
}
Picture(const Picture& p): height(p.height), width(p.width), data(new char[p.height * p.width]){ copyblock(0, 0, p); }
~Picture() { delete[] data; }
Picture& operator=(const Picture& p);
private:
int height, width;
char *data;
char& position(int row, int col){
return data[row * width + col];
}
char position(int row, int col) const{
return data[row * width + col];
}
void copyblock(int row, int col, const Picture& p){
for(int i=0; i<p.height; ++i){
for(int j=0; j<p.width; ++j)
position(i+row, j+col) = p.position(i, j);
}
}
void clear(int r1, int c1, int r2, int c2){
for(int r=r1; r<r2; ++r)
for(int c=c1; c<c2; ++c)
position(r, c) = ' ';
}
static int max(int m, int n) { return m > n ? m : n; }
void init(int h, int w){
height = h;
width = w;
data = new char[height * width];
}
};
ostream& operator<<(ostream&, const Picture&);
Picture frame(const Picture& p);
Picture operator&(const Picture&, const Picture&);
Picture operator|(const Picture&, const Picture&);
picturecontrol.cpp
#include <iostream>
#include "Picture.h"
using namespace std;
const char* init[] = {"Paris", "in the", "Spring"};
ostream& operator<<(ostream& o, const Picture& p){
for(int i=0; i<p.height; ++i){
for(int j=0; j<p.width; ++j){
o << p.position(i, j);
}
o << endl;
}
return o;
}
Picture frame(const Picture& p){
Picture r;
r.init(p.height + 2, p.width + 2);
for(int i=1; i < r.height-1; ++i){
r.position(i, 0) = '|';
r.position(i, r.width-1) = '|';
}
for(int j=1; j<r.width-1; ++j){
r.position(0, j) = '-';
r.position(r.height-1, j) = '-';
}
r.position(0, 0) = '+';
r.position(0, r.width-1) = '+';
r.position(r.height-1, 0) = '+';
r.position(r.height-1, r.width-1) = '+';
r.copyblock(1, 1, p);
return r;
}
Picture operator&(const Picture& p, const Picture& q){
Picture r;
r.init(p.height + q.height, Picture::max(p.width, q.width));
r.clear(0, p.width, p.height, r.width);
r.clear(p.height, q.width, r.height, r.width);
r.copyblock(0, 0, p);
r.copyblock(p.height, 0, q);
return r;
}
Picture operator|(const Picture& p, const Picture& q){
Picture r;
r.init(Picture::max(p.height, q.height), p.width+q.width);
r.clear(p.height, 0, r.height, p.width);
r.clear(q.height, p.width, r.height, r.width);
r.copyblock(0, 0, p);
r.copyblock(0, p.width, q);
return r;
}
int main(int argc, char const *argv[])
{
Picture p(init, 3);
Picture q = frame(p);
cout << frame(q & (p | q)) << endl;
return 0;
}