中国DOS联盟

这是《C++大全》上的一个DOS下弹出式窗口类C++示例，使用直接写视频VRAM方法实现窗口的显示，在DOS后期是一种成熟、使用率较高的方法。


窗口类的I/O层用纯C++代码＋BIOS中断实现，没用一个标准库函数。（除了速度快以外，这种代码比较易移植）


下面是该类完整的C++源码，包含用于演示的一个简单的main，该示例思路清晰，代码实现简洁易理解，是学习C++用于面向对象设计的较好的入门级示例。


代码在BC++3.1上编译通过。
///////////////////////////////////////////////////////////////////////////// // // A window class // PASS BC++ 3.1 // From CPP P633 // Type by AW@ng // // Form http://www.cn-dos.net/forum/ // ///////////////////////////////////////////////////////////////////////////// #include <iostream.h> #include <conio.h> #include <stdlib.h> #include <string.h> #include <dos.h> #include <bios.h> #include <stdio.h> ///////////////////////////////////////////////////////////////////////////// // // Globe functions and data declare // ///////////////////////////////////////////////////////////////////////////// /* Text colors, first 7 can also be used to specify background color. */ const enum clr {black, blue, green, cyan, red, magenta, brown, lightgray, darkgray, lightblue, lightgreen, lightcyan, lightred, lightmagenta, yellow, white, blink=128}; char far *vid_mem; //pointer to screen memory when in text mode int video_mode(); void goto_xy(int x, int y); void set_v_ptr(); void write_char(int x, int y, char ch, int attrib); void write_string(int x, int y, char *p, int attrib); ///////////////////////////////////////////////////////////////////////////// // // End Globe declare // ///////////////////////////////////////////////////////////////////////////// // // Start globe function define // ///////////////////////////////////////////////////////////////////////////// //Return the current video mode video_mode(void) { union REGS r; r.h.ah = 15; return int86(0x10, &r, &r) & 255; } //Set video mode video_address void set_v_ptr() { int vmode; vmode = video_mode(); if((vmode != 2) && (vmode != 3) && (vmode != 7)) { cout << endl << "Video must be in 80 column text mode" << endl; exit( 1 ); } //set proper address of video RAM if(vmode == 7) { vid_mem = (char *)0xB0000000; } else { vid_mem = (char *)0xB8000000; } } //Write character with specified attribute void write_char(int x, int y, char ch, int attrib) { char far *v; v = vid_mem; v += (y *160) + (x * 2); *v++ = ch; *v = attrib; } //Display string with specified attrib void write_string(int x, int y, char *p, int attrib) { register int i; char far *v; v = vid_mem; v += (y * 160) + (x * 2); for(i = y; *p ; i++) { *v++ = *p++; *v++ = attrib; } } //Send the cursor to the specified X, Y position void goto_xy(int x, int y) { union REGS r; r.h.ah = 2; r.h.dl = x; r.h.dh = y; r.h.bh = 0; int86(0x10, &r, &r); } ///////////////////////////////////////////////////////////////////////////// // // Start class declare // ///////////////////////////////////////////////////////////////////////////// class wintype { int leftx; //define where window goes on the screen int upy; //upper left coordinate int rightx; int downy; //lower right coordinate int border; //if non-zero,border displayed int active; //non-zero if window is currently on screen char *title; //window title int curx, cury; //current cursor location in window char *buf; //points to window's buffer char color; //window text color //private functions void save_screen(); //save screen so it can be restored void restore_screen(); //restore the original screen void draw_border(); //draw a window's border void display_title(); //display window title public: wintype(int lx, int uy, //upper left int re, int ly, //lower right int b = 1, //non-zero for border char *mess = ""); //title message ~wintype() { winremove(); delete buf; } void winput(); //display a window void winremove(); //remove a window int winputs(char *s); //write a string to the window int winxy(int x, int y); //go to X, Y relative to window void wingets(char *s); //input a string from a window int wingetche(); //input a character from a window void wincls(); //clears the window void wincleol(); //clears to end-of-line void setcolor(char c) {color = c; } char getcolor() {return color; } void setbkcolor(char c) {color = (color | (c << 4)); } char getbkcolor() {return (color >> 4) & 127; } friend wintype &operator << (wintype &o, char *s); friend wintype &operator >> (wintype &o, char *s); }; ///////////////////////////////////////////////////////////////////////////// // // End class declare // ///////////////////////////////////////////////////////////////////////////// //Construct a window. wintype::wintype(int lx, int uy, int rx, int ly, int b, char *mess ) { if(lx < 0 ) lx = 0 ; if(rx > 79) rx = 79; if(uy < 0 ) uy = 0 ; if(ly > 24) ly = 24; leftx = lx ; upy = uy ; rightx = rx ; downy = ly ; border = b ; title = mess ; active = 0 ; curx = cury = 0; buf = new char; if( !buf ) { cout << "\nAllocation window buffer error\n"; exit( 1 ); } color = white; } //Display a window void wintype::winput() { //get active window if( !active ) //not currently in use { save_screen(); //save the current screen active = 1; //set active flag } else { return; //already on screen } if( border ) { draw_border(); } display_title(); //position cursor in apper left corner goto_xy(leftx + curx + 1, upy + cury +1); } //Remove the window and restore prior screen contents. void wintype::winremove() { if(!active) //con't remove a non-active window { return; } restore_screen(); //restore the original screen active = 0; //restore_video } //Draw a border around the window void wintype::draw_border() { register int i; char far *v; char far *t; v = vid_mem; t = v; for(i = leftx + 1; i < rightx; i++) { v += (upy * 160) + (i * 2); *v ++ = 196; *v = color; v = t; v += (downy * 160) + (i * 2); *v ++ = 196; *v = color; v = t; } for(i = upy + 1; i < downy; i++) { v += (i * 160) + (leftx * 2); *v ++ = 179; *v = color; v = t; v += (i * 160) + (rightx * 2); *v ++ = 179; *v = color; v = t; } //draw the corners write_char(leftx, upy, 218, color); write_char(leftx, downy, 192, color); write_char(rightx, upy, 191, color); write_char(rightx, downy, 217, color); } //Display the window's title void wintype::display_title() { register int x, len; x = leftx; len = strlen(title); len = (rightx - x- len)/2; if( len < 0 ) return; x = x + len +1; write_string(x, upy, title, color); } //Save screen so ti can be restored after window is removed void wintype::save_screen() { register int i, j ; char far *v ; char far *t ; char *buf_ptr ; buf_ptr = buf; v = vid_mem; for(i = upy; i < downy+1; i++) { for(j = leftx; j < rightx+1; j++) { t = (v + (i*160) + (j*2)); *buf_ptr++ = *t++; *buf_ptr++ = *t; *(t - 1) = ' '; //clear the window } } } //Restore a portion of the screen void wintype::restore_screen() { register int i, j ; char far *v ; char far *t ; char *buf_ptr ; buf_ptr = buf; //computer pointer to video RAM v = vid_mem; t = v; for(i = upy; i < downy+1; i++) { for(j = leftx; j < rightx+1; j++) { v = t; v += (i*160) + j*2; *v++ = *buf_ptr++; //write the character *v = *buf_ptr++; //write the attrib } } } //Write a string at the current cursor position win the specified window int wintype::winputs(char *s) { register int x, y; char far *v; //make sure window is active if ( !active ) return 0; x = curx + leftx + 1; y = cury + upy + 1; v = vid_mem; v += (y * 160) + (x * 2); for( ; *s; s++ ) { if(y >= downy) { return 1; } if(x >= rightx) { return 1; } if(*s == '\n') { y++; x = leftx + 1; v = vid_mem; v += (y * 160) + (x * 2);; cury++; curx = 0; } else { curx++; x++; *v++ = *s; *v++ = color; } winxy(curx,cury); } return 1; } /* Postion cursor in a window at specified location Return 0 if out of range; non-zero otherwise. */ int wintype::winxy(int x, int y) { if(x < 0 || x+leftx >= rightx-1) { return 0; } if(y < 0 || y+upy >= downy-1) { return 0; } curx = x; cury = y; goto_xy(leftx + x + 1, upy + y + 1); return 1; } //read a string from a window void wintype::wingets(char *s) { char ch, *temp; temp = s; for(;;) { ch = wingetche(); switch(ch) { case '\r' : { *s = '\0'; return ; } case '\b' : if(s > temp) { s--; curx--; if(curx < 0) { curx = 0; } winxy(curx, cury); write_char(leftx + curx + 1, upy + cury +1, ' ', color); } break; default : { *s = ch; s++; } } } } /* Input a keystroke inside a window Returns full 16 bit keyboard code. */ wintype::wingetche() { union inkey { char ch; int i; } c; union REGS r; if( !active ) return 0; winxy(curx, cury); r.h.ah = 0; c.i = int86(0x16, &r, &r); if( c.ch ) { switch( c.ch ) { case '\r' : { break; } case '\b' : { break; } default: { if( curx + leftx < rightx -1 ) { write_char(leftx + curx +1, upy + cury +1, c.ch, color ); curx++; } } } } if(cury < 0) cury = 0; if(cury + upy > downy -2) { cury--; winxy(curx, cury); } return c.i; } //Clear a window void wintype::wincls() { register int i, j; char far *v, far *t; v = vid_mem; t = v; for(i = upy +1; i < downy; i++) for(j = leftx + 1; j < rightx; j++) { v = t; v += (i * 160) + (j * 2); *v++ = ' '; *v = color; } curx = 0; cury = 0; } //Clear to end of line void wintype::wincleol() { register int i, x, y; x = curx; y = cury; winxy(curx, cury); for(i = curx; i < rightx; i++) { winputs(" "); } winxy(x, y); } //Output to a window wintype &operator << (wintype &o, char *s) { o.winputs(s); return o; } //Input from a window wintype &operator >> (wintype &o, char *s) { o.wingets(s); return o; } ///////////////////////////////////////////////////////////////////////////// // // Main program here // ///////////////////////////////////////////////////////////////////////////// main() { char s; set_v_ptr(); //set the video memory pointer wintype w1(1, 10, 20, 20, 1, "My window #1"); wintype w2(40, 1, 60, 20, 1, "My window #2"); wintype w3(40, 5, 60, 20, 2, "My window #3"); w1.winput(); w2.winput(); w1.setcolor(blue); w2.setcolor(green); w3.setcolor(red); getch(); w1.winremove(); w2.winremove(); getch(); w1.winput(); w2.winput(); w3.winput(); getch(); w1.winremove(); getch(); w3.winremove(); getch(); w2.winremove(); getch(); w1.winput(); w2.winput(); getch(); w1 >> s; w1.winxy( 0, 0 ); getch(); w1.winputs("Hi there\n"); w1.winputs("Windows is fan"); w1 << "\n"; w1 >> s; w1 << "This \nis " << "a test" << "\n"; w2 << "this is a test"; w2.winxy(3, 4); w2 << "at location 3,4"; w1 << "This is anther test for you to see\n"; w1 >> s; w3.winput(); w3 >> s; w3.winremove(); getch(); w1.winxy(0, 0); w1.setcolor(red); w1.setbkcolor(cyan); w1.winputs("PROMPT:"); w1.setcolor(white); w1.setbkcolor(black); w1 >> s; w2.winxy(0, 4); w2.setcolor(yellow); w2.setbkcolor(green); w2.winputs(s); w2 >> s; w2.wincls(); w1.winxy(5, 0); w1.wincleol(); w2 >> s; w1.winremove(); w2.winremove(); w1.winput(); w1 >> s; return 0; }


BC＋＋下的代码copy到Win下有个别地方显示板式不同，没太大影响，没做调整。


这个示例是我学习C++的时候完成的，代码中的字符都是本人一个个敲进电脑的，一是为了学习BC++3.1的IDE，另外也能加深对代码的理解，书中个别印错的地方已经修正。现发上来和初学C++的朋友和爱好者共享。


那时的C++实现标准是1989年的2.1版，没现在这么复杂，模板和异常还是发展方向，名字空间，泛型听都没听说过，正因为这样，更能有助于学习C++面向对象的思维方法，而不是专注于代码的实现，这才是C++和C的本质区别。


2.1版的C++个人认为是比较纯淬的C++，能很好的用OO实现C++的初衷“使程序结构清晰、易于扩展、易于维护而不失其效率”，没有多余的东西，“增一分太肥，减一分太瘦”。


现在C++加入了各种“先进”的特性后，发展到目前的C++0X，连C++的发明人也不得不承认有些“四不象”了，真可惜了这一优美的程序设计语言。


题外：
关于BC＋＋3的经典有了最新证据，Win7下的BC++3.1比在Windows3.1时代好用，把“环境”项里的25行显示改为50行，再得宜于Win7完善高效的内存管理，用起来真是舒服，再看看Win7的自家人VC6，“该程序有兼容性问题，请......”，我真的哭笑不得。

以前的ID不知为什么不能登录了，重注册了一个。

都是DOS老人,同好!
Win9x/2k/xp都支持DOS程序,而且也支持dos32(不管是watcom还是djgpp编译出来的),但在vista测试,上述两种程序都不支持.
Win7没用过,支持DOS?
如果支持,估计也支持dos32.

dos时刻最经典的"直接写屏"模式,绕开DOS的API和BIOS,直接对显存编程,提高显示速度.