Thread: pls post here tricks that you know of in C/C++, thanks

Why don't you ask them to write your entire website for you while your at it too?

that's clever...
too lazy to try it out, though.

Ok here is a lame trick..

When you do graphics in c++ (16 bit for dos) Instead of using getimage and stuff you can draw an image and when you want it just move it and overdraw the previous one with black or the backgrounf colour... Using a loop.

Below is an entire game pack done with this simple logic..




# include <process.h>
# include <dos.h>
#include <graphics.h>
#include <stdlib.h>
#include <stdio.h>
#include <conio.h>
# include <iostream.h>
int i,k,y=180,select,counter,counter1;
int lk=1,tic1=0,tic2=0,vas=10,kit=10;



void inig()
{

closegraph();
int gdriver = DETECT, gmode, errorcode;
initgraph(&gdriver, &gmode, "");


}

void start()
{
inig();
int i;
setcolor(8);
for (i=0;i<640;i++)
{ line (i,0,i,15);
line (i,480,i,465); }

settextjustify(CENTER_TEXT, CENTER_TEXT);
settextstyle(GOTHIC_FONT, HORIZ_DIR, 5);
setcolor(9);
settextstyle (10,HORIZ_DIR,5);
outtextxy(300,75,"Gamez Center");
delay(100);
setcolor(RED);
settextstyle (1,HORIZ_DIR,5);
outtextxy(310,28, " X ");
setcolor(6);
settextstyle (8,HORIZ_DIR,2);
outtextxy(300,31, " Group ");

settextstyle (13,HORIZ_DIR,2);
outtextxy(310,39, " Presents ");

settextstyle (8,HORIZ_DIR,2);
setcolor(27);
outtextxy(300,175, "1) Tic Tac Toe");
settextstyle (8,HORIZ_DIR,2);
outtextxy(300,210, "2) Battle Ship");
outtextxy(300,245, "3) Run Man ");
outtextxy(300,280, "4) Snake ");
outtextxy(300,315, "5) Credits ");
outtextxy(300,350, "6) Exit ");

}

















void circ(int cho)
{
setcolor(GREEN);
if(cho==1)
circle(200,100,30);
if(cho==2)
circle(300,100,30);
if(cho==3)
circle(400,100,30);
if(cho==4)
circle(200,200,30);
if(cho==5)
circle(300,200,30);
if(cho==6)
circle(400,200,30);
if(cho==7)
circle(200,300,30);
if(cho==8)
circle(300,300,30);
if(cho==9)
circle(400,300,30);

}




void cross(int tr)
{
setcolor(GREEN);
if(tr==1)
{
moveto(200,60);
lineto(160,140);
lineto(240,140);
lineto(200,60);
}

if(tr==2)
{
moveto(300,60);
lineto(260,140);
lineto(340,140);
lineto(300,60);
}

if(tr==3)
{
moveto(400,60);
lineto(360,140);
lineto(440,140);
lineto(400,60);
}

if(tr==4)
{
moveto(200,160);
lineto(160,240);
lineto(240,240);
lineto(200,160);
}

if(tr==5)
{
moveto(300,160);
lineto(260,240);
lineto(340,240);
lineto(300,160);
}

if(tr==6)
{
moveto(400,160);
lineto(360,240);
lineto(440,240);
lineto(400,160);
}

if(tr==7)
{
moveto(200,260);
lineto(160,340);
lineto(240,340);
lineto(200,260);
}

if(tr==8)
{
moveto(300,260);
lineto(260,340);
lineto(340,340);
lineto(300,260);
}

if(tr==9)
{
moveto(400,260);
lineto(360,340);
lineto(440,340);
lineto(400,260);
}




}


void win(int wi)
{
if(wi==1)
{
for(int crs=0;crs<20;crs++)
{

moveto(400-crs,60-crs);
lineto(360-crs,140-crs);
lineto(440-crs,140-crs);
lineto(400-crs,60-crs);

moveto(400-crs,160-crs);
lineto(360-crs,240-crs);
lineto(440-crs,240-crs);
lineto(400-crs,160-crs);

moveto(400-crs,260-crs);
lineto(360-crs,340-crs);
lineto(440-crs,340-crs);
lineto(400-crs,260-crs);

delay(10);


}

}

if(wi==2)
{
for(int crs=0;crs<20;crs++)
{
moveto(200-crs,260-crs);
lineto(160-crs,340-crs);
lineto(240-crs,340-crs);
lineto(200-crs,260-crs);

moveto(300-crs,260-crs);
lineto(260-crs,340-crs);
lineto(340-crs,340-crs);
lineto(300-crs,260-crs);

moveto(400-crs,260-crs);
lineto(360-crs,340-crs);
lineto(440-crs,340-crs);
lineto(400-crs,260-crs);
delay(10);


}

}


if(wi==3)
{
for(int crs=0;crs<20;crs++)
{
moveto(400-crs,60-crs);
lineto(360-crs,140-crs);
lineto(440-crs,140-crs);
lineto(400-crs,60-crs);

moveto(300-crs,160-crs);
lineto(260-crs,240-crs);
lineto(340-crs,240-crs);
lineto(300-crs,160-crs);

moveto(200-crs,260-crs);
lineto(160-crs,340-crs);
lineto(240-crs,340-crs);
lineto(200-crs,260-crs);
delay(10);




}





}

if(wi==5)
{
for(int crs=0;crs<20;crs++)
{
moveto(200-crs,60-crs);
lineto(160-crs,140-crs);
lineto(240-crs,140-crs);
lineto(200-crs,60-crs);

moveto(200-crs,160-crs);
lineto(160-crs,240-crs);
lineto(240-crs,240-crs);
lineto(200-crs,160-crs);

moveto(200-crs,260-crs);
lineto(160-crs,340-crs);
lineto(240-crs,340-crs);
lineto(200-crs,260-crs);

delay(10);

}
}


if(wi==6)
{
for(int crs=0;crs<20;crs++)
{
moveto(200-crs,60-crs);
lineto(160-crs,140-crs);
lineto(240-crs,140-crs);
lineto(200-crs,60-crs);

moveto(300-crs,160-crs);
lineto(260-crs,240-crs);
lineto(340-crs,240-crs);
lineto(300-crs,160-crs);

moveto(400-crs,260-crs);
lineto(360-crs,340-crs);
lineto(440-crs,340-crs);
lineto(400-crs,260-crs);

delay(10);

}
}


setcolor(RED);
settextstyle (8,HORIZ_DIR,3);
outtextxy(100,410, "The Computer Wins The Game");
delay(3000);
closegraph();
system("game.exe");

}


void ticlogic()
{
int x,y,x1,y1;
x=200;
y=100;
cross(9);
prog:
setcolor(GREEN);
circle(x,y,10);
x1=x;
y1=y;

select=getche();
setcolor(BLACK);
circle(x1,y1,10);
if(select==0x4d)
{
x=x+100;
if(x>400)
x=200;
}
if(select==0x4b)
{
x=x-100;
if(x<200)
x=400;
}

if(select==0x48)
{
y=y-100;
if(y<100)
y=300;
}

if(select==0x50)
{
y=y+100;
if(y>300)
y=100;

}

if(select==27)
exit(0);

if(select==13 && vas==10)
{
if(x==400 && y==100)
{
kit=153;
lk=131;
tic1=432;
tic2=412;
circ(3);
delay(1000);
cross(7);

}
if(kit==153 && x==200 && y==100)
{
circ(1);
delay(1000);
cross(7);
win(2);

}
if(kit==153 && x==300 && y==100)
{
circ(2);
delay(1000);
cross(7);
win(2);

}
if(kit==153 && x==200 && y==200)
{
circ(4);
delay(1000);
cross(7);
win(2);

}
if(kit==153 && x==300 && y==200)
{
circ(5);
delay(1000);
cross(7);
win(2);

}
if(kit==153 && x==400 && y==200)
{
circ(6);
delay(1000);
cross(7);
win(2);

}

if(kit==153 && x==300 && y==300)
{
circ(8);
delay(1000);
cross(1);
kit=323;
}
if(kit==323 && x==300 && y==100)
{
circ(2);
delay(1000);
cross(4);
win(5);
}
if(kit==323 && x==200 && y==200)
{
circ(4);
delay(1000);
cross(5);
win(6);
}

if(kit==323 && x==300 && y==200)
{
circ(5);
delay(1000);
cross(4);
win(5);
}
if(kit==323 && x==400 && y==200)
{
circ(6);
delay(1000);
cross(4);
win(5);
}

}










if(select==13)
{
vas==223;
if(x==300 && y==100 && kit==10)
{
circ(2);
delay(1000);
lk=0;
cross(3);
tic1=10;

}

if(tic2==10)
{
if(x==300 && y==200)
{
circ(5);
delay(1000);
cross(8);
win(2);


}
if(x==300 && y==300)
{
circ(8);
delay(1000);
cross(5);
win(3);

}
if(x==200 && y==100)
{
circ(1);
delay(1000);
cross(5);
win(3);

}
if(x==200 && y==200)
{
circ(4);
delay(1000);
cross(5);
win(3);


}


}






if(tic1==10 && tic2==0)
{ vas=313;


if(x==200 && y==100)
{
circ(1);
delay(1000);
cross(6);
win(1);

}
if(x==200 && y==200)
{
circ(4);
delay(1000);
cross(6);
win(1);

}
if(x==300 && y==200)
{
circ(5);
delay(1000);
cross(6);
win(1);

}
if(x==200 && y==300)
{
circ(7);
delay(1000);
cross(6);
win(1);

}
if(x==300 && y==300)
{
circ(8);
delay(1000);
cross(6);
win(1);

}


if(x==400 && y==200)
{
circ(6);
delay(1000);
cross(7);
tic2=10;
}


}



if(lk==1 && x==200 && y==100 && tic2==0)
{ vas=434;
circ(1);
delay(1000);
cross(3);
counter=1;
}
prog1:
if(counter==1)
{ vas=422;

if(x==400 && y==200)
{

circ(6);
delay(1000);
cross(7);
counter=10;
goto prog1;
}


if(x==300 && y==100)
{
circ(2);
delay(1000);
cross(6);
win(1);
}

if(x==200 && y==200)
{circ(4);
delay(1000);
cross(6);
win(1);
}
if(x==300 && y==200)
{
circ(5);
delay(1000);
cross(6);
win(1);
}
if(x==200 && y==300)
{
circ(7);
delay(1000);
cross(6);
win(1);
}
if(x==300 && y==300)
{
circ(8);
delay(1000);
cross(6);
win(1);


}}
if(counter==10)
{ vas=4423;

if(x==300 && y==100)
{
circ(2);
delay(1000);
cross(8);
win(2);


}

if(x==200 && y==200)
{
circ(4);
delay(1000);
cross(8);
win(2);
}

if(x==300 && y==200)
{
circ(5);
delay(1000);
cross(8);
win(2);
}
if(x==300 && y==300)
{
circ(8);
delay(1000);
cross(5);
win(3);


}

}

}


goto prog;


}



void doub()
{

closegraph();
char nam1[' '],nam2[' '];
inig();
settextstyle(7, HORIZ_DIR, 2);
setcolor(GREEN);
rectangle(1,479,639,1);
rectangle(2,478,638,2);
setcolor(8);
outtextxy(60,75, "Enter the first players name >> ");
gotoxy(60,6);
cin>>nam1;
outtextxy(60,105, "Enter the second players name >> ");
gotoxy(60,8);
cin>>nam2;
inig();
setcolor(GREEN);
rectangle(1,479,639,1);
rectangle(2,478,638,2);
setcolor(BLUE);
line(150,150,450,150);
line(150,250,450,250);
line(250,50,250,350);
line(350,50,350,350);
line(150,151,450,151);
line(150,251,450,251);
line(251,50,251,350);
line(351,50,351,350);
settextstyle(8, HORIZ_DIR, 2);
setcolor(GREEN);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");

int xq=200,yq=100;
int getv;
si:
setcolor(GREEN);
circle(xq,yq,10);
getv=getche();
setcolor(BLACK);
circle(xq,yq,10);

if(getv==0x4b)
{
xq=xq-100;
if(xq<200)
xq=400;
}
if(getv==0x4d)
{
xq=xq+100;
if(xq>400)
xq=200;
}
if(getv==0x48)
{
yq=yq-100;
if(yq<100)
yq=300;
}
if(getv==0x50)
{
yq=yq+100;
if(yq>300)
yq=100;
}
if(getv==27)
exit(0);
if(getv==13 && xq==200 && yq==100)
{
circ(1);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}
if(getv==13 && xq==300 && yq==100)
{
circ(2);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}

if(getv==13 && xq==400 && yq==100)
{
circ(3);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}

if(getv==13 && xq==200 && yq==200)
{
circ(4);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}

if(getv==13 && xq==300 && yq==200)
{
circ(5);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}

if(getv==13 && xq==400 && yq==200)
{
circ(6);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}

if(getv==13 && xq==200 && yq==300)
{
circ(7);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}

if(getv==13 && xq==300 && yq==300)
{
circ(8);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}

if(getv==13 && xq==400 && yq==300)
{
circ(9);
setcolor(BLACK);
outtextxy(60,375,nam1);
outtextxy(200,375,"to play");
setcolor(GREEN);
outtextxy(60,375,nam2);
outtextxy(200,375,"to play");

}


goto si;

























}


void tictactoe()

{
for(int lines=17;lines<500;lines++)
{
setcolor(BLACK);
line(0,lines,800,lines);
delay(1);
}

int abc;
abc=0;
pro:
closegraph();
inig();
setcolor(GREEN);
rectangle(1,479,639,1);
rectangle(2,478,638,2);
int jkl,ys=225;
for(int re=0;re<10;re++)
{
setcolor(re);
circle(450,225,re);
}
pro1:
if(abc==0)
{
abc=1;
setcolor(RED);
settextjustify(CENTER_TEXT, CENTER_TEXT);
settextstyle(8, HORIZ_DIR, 2);
outtextxy(300,175, "TIC TAC TOE");
setcolor(BLUE);
outtextxy(300,225, "1) Two Player Mode");
outtextxy(300,275, "2) Single Player Mode");
pro2:
jkl=getche();
for(int re=0;re<10;re++)
{
setcolor(BLACK);
circle(450,ys,re);
}


if(jkl==0x48)
{
ys=ys-50;
if(ys<225)
ys=275;

}
if(jkl==0x50)
{
ys=ys+50;
if(ys>275)
ys=225;

}
if(jkl==27)
{
exit(0);
}
for(re=0;re<10;re++)
{
setcolor(re);
circle(450,ys,re);
delay(10);
}
int ys1;
abc=0;
if(ys==275 && jkl==13)
{
closegraph();
inig();
goto single;

}
if(ys==225 && jkl==13)
{
doub();

}

goto pro2;

}
single:
setcolor(GREEN);
rectangle(1,479,639,1);
rectangle(2,478,638,2);

setcolor(BLUE);
line(150,150,450,150);
line(150,250,450,250);
line(250,50,250,350);
line(350,50,350,350);
line(150,151,450,151);
line(150,251,450,251);
line(251,50,251,350);
line(351,50,351,350);
ticlogic();

}






















void select1()
{
settextstyle (8,HORIZ_DIR,1);
if(y==355)
{
setcolor(BLUE);
for (i=0;i<640;i++)
{ line (i,0,i,15);}
setcolor(GREEN);
outtextxy(1,1, " The program is exiting from the console mode please wait...... ");
delay(3000);
for(int lines=17;lines<500;lines++)
{
setcolor(BLACK);
line(0,lines,800,lines);
delay(3);
}

closegraph();
exit(0);
}
if(y==320)
{
setcolor(8);
rectangle(635,520,430,170);
rectangle(634,519,429,169);
setcolor(WHITE);
settextstyle (6,HORIZ_DIR,1);
outtextxy(530,185, "Credits");
for(int ef=450;ef>200;ef--)

{
setcolor(9);
settextstyle (6,HORIZ_DIR,1);
outtextxy(530,ef, "Shefiu - The Leader");
delay(15);
setcolor(BLACK);
outtextxy(530,ef, "Shefiu - The Leader");
}
delay(20);
for(ef=450;ef>200;ef--)

{
setcolor(9);
settextstyle (6,HORIZ_DIR,1);
outtextxy(530,ef, "Vasanth - The Mind");
delay(15);
setcolor(BLACK);
outtextxy(530,ef, "Vasanth - The Mind");
}
delay(20);
for(ef=450;ef>200;ef--)

{
setcolor(9);
settextstyle (6,HORIZ_DIR,1);
outtextxy(530,ef, "Akhil - Reflection");
delay(15);
setcolor(BLACK);
outtextxy(530,ef, "Akhil - Reflection");
}
delay(20);
for(ef=450;ef>200;ef--)

{
setcolor(9);
settextstyle (6,HORIZ_DIR,1);
outtextxy(530,ef, "Devo - Assimilator");
delay(15);
setcolor(BLACK);
outtextxy(530,ef, "Devo - Assimilator");
}
delay(20);
for(ef=450;ef>200;ef--)

{
setcolor(9);
settextstyle (6,HORIZ_DIR,1);
outtextxy(530,ef, "Ridwaan - The Boss");
delay(15);
setcolor(BLACK);
outtextxy(530,ef, "Ridwaan - The Boss");
}
delay(20);
for(ef=450;ef>200;ef--)

{
setcolor(9);
settextstyle (6,HORIZ_DIR,1);
outtextxy(530,ef, "MH - Listening");
delay(15);
setcolor(BLACK);
outtextxy(530,ef, "MH - Listening");
}
delay(20);
for(ef=450;ef>230;ef--)

{
setcolor(9);
settextstyle (6,HORIZ_DIR,4);
outtextxy(530,ef-10, "....Group X");
delay(15);
setcolor(BLACK);
outtextxy(530,ef-10, "....Group X");
}


delay(1000);
setcolor(9);
settextstyle (6,HORIZ_DIR,1);
outtextxy(530,ef-10, "Shefiu - The Leader");
outtextxy(530,ef+20, "Vasanth - The Mind");
outtextxy(530,ef+50, "Akhil - Reflection");
outtextxy(530,ef+80, "Devo - Assimilator");
outtextxy(530,ef+110, "Ridwaan - The Boss");
outtextxy(530,ef+140, "MH - Listening");
outtextxy(530,ef+170, "Form....");
settextstyle (6,HORIZ_DIR,4);
outtextxy(530,ef+210, " ...The Group X");
delay(7000);
start();
}

if(y==180)
{ setcolor(BLUE);
for (i=0;i<640;i++)
{ line (i,0,i,15);

}

setcolor(GREEN);
outtextxy(1,1," Tic Tac Toe Game is loading please wait...................");
delay(500);
tictactoe();
start();

}

}



void point()
{
int x;
int x1,y1;
x1=0;
y1=0;
x=400;
prog:
setcolor(BLACK);
for(int ci=0;ci<10;ci++)
{
circle(x1,y1,ci);
}

setcolor(GREEN);
for(ci=0;ci<10;ci++)
{
setcolor(ci);

circle(x,y,ci);
delay(20);
}

x1=x;
y1=y;
k=getche();
if(k==0x50)
y=y+35;
if(y>355)
y=180;
if(k==27)
exit(0);
if(k==0x48)
y=y-35;
if(y<180)
y=355;
if(k==13)
select1();
goto prog;

}

void main()
{
inig();
start();
point();
tictactoe();
}



/* Please use code tags next time, just posting it makes it next to unreadable. You could also just attach the file. hth - nv, mod. */

Instead of using all that code to fake the animation, use a double buffer and blit the image. I can do it in assembly in about 10 lines, and in C in about 8. For good animation you have to use a double buffer or flip the pointers. You never want the image to disappear from the screen, or the user will see it as a brief flash or flicker since the image does disappear for a very brief amount of time. However, the human eye will catch this flicker.

One good result/trick of the AND operation is this.

number MOD (power of 2)

is the same as

number AND ((power of 2)-1).

so x mod 256

is the same as

x AND 255

x AND 255 is much much faster than x mod 256


It would be interesting to see if the compilers would catch this in an optimization loop. Use the slower method and then look at the asm that the compiler generates.

Another technique that may or may not help you is getting access to 32-bit opcodes and 32-bit addresses in 16-bit segments.

either do this:

asm
{
db 66h
stosw
}

or you can use emit() to emit bytes directly into the code stream.
Personally, I would use a separate asm file.


Since stosw is preceeded by the 32-bit opcode prefix 66h, it will actually execute stosd.

The 32-bit address prefix is 67h.


Most compilers should produce asm from your C code that already takes advantage of these tricks and more. There are many many tricks to speed up pipelined processors. For more information look on a search engine. I have a URL for this, but it is all in assembly, or most of it, and would probably only serve to confuse you.

One good rule of thumb in any code is don't jump around a lot. Every time you call another function, a new stack frame is created and if that function has parameters, a lot of pushing and popping is going on. This is true for all calls. The more you jump around, the slower your code will execute even with jump optimization on. The compiler will attempt to optimize your jumps but it is possible to structure your code in such a way as to defeat this optimization. So in tight loops that need to be fast, make sure you do not jump or call out of that loop or you will slow it down.

Also for tight loops and fast code you should make use of the register prefix on variables. Now there are a limited number of registers, but this prefix will tell the compiler that you prefer your variables to be stored in registers. This is optional to the compiler and can only be done if there are indeed any registers that are free to be used. However in small loops with limited variables this can speed up your code somewhat. You can turn automatic register variables on in your compiler options as well. The default scheme then would be for your compiler to attempt to store as many variables as it can in registers instead of memory.

To really understand how to make your code faster, in my opinion, I think you would need to understand a bit of assembly. Many might disagree on this point, but my knowledge of assembly has helped a lot.

And, of course, make sure that you use a profiler. Often times the problem areas might not be exactly where the programmer 'thinks' they are. The profiler will give you a much better picture of what's going on when and where.

My last optimization is with arrays. Lots of people use 2D arrays. I've read time and time again that these access slower than 1D.

To access a 1D array, but treat it like a 2D you would do

row*width+column for row major ordering. There is also column major ordering but same idea. Also if your array is a power of 2, and it should be, then you can use bitshifts to eliminate the mul inherent in the formula.

But I could go on and on about tricks and optimizations. Some of them are mute points on todays processors and compilers and some are not. Like I said look this up on www.google.com and you can find out a lot more information. But, in your code, try to work with the processor instead of against it and your code will get along much better with the CPU.

bubba, thanks, that's quite an effort you posted up here,

prelude, it's commutative,

unregisterd, what do you mean? i want to build this website myself,

thanks all but i hope to get more tricks so that later on i can have make up sections for the website,

Any way i am new to programming...
How is the graphics anyway...

Those tricks are amazing.