C++ Programming Code Examples
C++ > Computer Graphics Code Examples
Graphics program in which three balls move in three concentric oval orbit
/* Graphics program in which three balls move in three concentric oval orbit
without ever colliding. */
#define R 5
#include<iostream.h>
#include<conio.h>
#include<graphics.h>
#include<math.h>
#include<dos.h>
#include<stdlib.h>
void main()
{
void orbit(void);
int d=DETECT,m;
initgraph(&d,&m,"e:\tcc\bgi");
float xx,yy,aa=15,bb=50,x,y,X,Y,a=34,b=0,A=100,B=60,ex,sq;
setcolor(14);
// orbit();
for(float i=0;i<=720;i+=.1)
{
x=a*cos(i+10)-a*sin(i+10);
y=b*sin(i+10)+a*cos(i+10);
X=A*cos(i+20)-B*sin(i+20+90);
Y=B*sin(i+20)+B*cos(i+20+90);
xx=aa*cos(i);
yy=bb*sin(i);
setcolor(14);
setfillstyle(1,14);
circle(x+100,y+100,R);
floodfill(x+100,y+100,14);
setcolor(14);
setfillstyle(1,14);
circle(xx+100,yy+100,R);
floodfill(xx+100,yy+100,14);
setcolor(14);
setfillstyle(1,14);
circle(X+100,Y+100,R);
floodfill(X+100,Y+100,14);
putpixel(X+100,Y+100,4);
delay(100);
setcolor(0);
setfillstyle(1,0);
circle(x+100,y+100,R);
floodfill(x+100,y+100,0);
setcolor(0);
setfillstyle(1,0);
circle(xx+100,yy+100,R);
floodfill(xx+100,yy+100,0);
setcolor(0);
setfillstyle(1,0);
circle(X+100,Y+100,R);
floodfill(X+100,Y+100,0);
if(kbhit())
exit(1);
orbit();
}
getch();
}
void orbit()
{
for(float i=0;i<=60;i+=1)
{
float xx,yy,aa=15,bb=50,x,y,X,Y,a=34,b=0,A=100,B=60,ex,sq;
x=a*cos(i)-a*sin(i);
y=b*sin(i)+a*cos(i);
X=A*cos(i)-B*sin(i+90);
Y=B*sin(i)+B*cos(i+90);
xx=aa*cos(i);
yy=bb*sin(i);
putpixel(x+100,y+100,14);
putpixel(X+100,Y+100,14);
putpixel(xx+100,yy+100,14);
}
}
The exit function terminates the program normally. Automatic objects are not destroyed, but static objects are. Then, all functions registered with atexit are called in the opposite order of registration. The code is returned to the operating system. An exit code of 0 or EXIT_SUCCESS means successful completion. If code is EXIT_FAILURE, an indication of program failure is returned to the operating system. Other values of code are implementation-defined. Calls all functions registered with the atexit() function, and destroys C++ objects with static storage duration, all in last-in-first-out (LIFO) order. C++ objects with static storage duration are destroyed in the reverse order of the completion of their constructor. (Automatic objects are not destroyed as a result of calling exit().)
Compute cosine. Returns the cosine of an angle of x radians. cos() function is a library function of cmath header, it is used to find the cosine of the given number (angle), it accepts a number (x) and returns the cosine of angle x radians. In trigonometry, the cos function of a right-angled triangle is defined as the length of the adjacent side over the longest side, i.e., the hypotenuse. The cos function in C++ works precisely like the cosine function in trigonometry. The return value of the cos function is the cosine of an angle given in radian. Function returns cosine of x radians.
The kbhit is basically the Keyboard Hit. This function is present at conio.h header file. So for using this, we have to include this header file into our code. The functionality of kbhit() is that, when a key is pressed it returns nonzero value, otherwise returns zero. kbhit() is used to determine if a key has been pressed or not. If a key has been pressed then it returns a non zero value otherwise returns zero.
The header file graphics.h contains putpixel() function which plots a pixel at location (x, y) of specified color. Where, (x, y) is the location at which pixel is to be put, and color specifies the color of the pixel. To put a pixel on the screen at a particular position, calling the pixel() function is a good way. This function takes three parameters as the position of the pixel and also the color of the pixel.
In computer programming, we use the if statement to run a block code only when a certain condition is met. An if statement can be followed by an optional else statement, which executes when the boolean expression is false. There are three forms of if...else statements in C++: • if statement, • if...else statement, • if...else if...else statement, The if statement evaluates the condition inside the parentheses ( ). If the condition evaluates to true, the code inside the body of if is executed. If the condition evaluates to false, the code inside the body of if is skipped.
floodfill function is used to fill an enclosed area. Current fill pattern and fill color is used to fill the area.(x, y) is any point on the screen if (x,y) lies inside the area then inside will be filled otherwise outside will be filled, border specifies the color of boundary of area. To change fill pattern and fill color use setfillstyle.
This library function is declared in graphics.h and used to draw a circle; it takes centre point coordinates and radius. Circle function is used to draw a circle with center (x,y) and third parameter specifies the radius of the circle. The code given below draws a circle. Where, (x, y) is center of the circle. 'radius' is the Radius of the circle.
As the name already suggests, these operators help in assigning values to variables. These operators help us in allocating a particular value to the operands. The main simple assignment operator is '='. We have to be sure that both the left and right sides of the operator must have the same data type. We have different levels of operators. Assignment operators are used to assign the value, variable and function to another variable. Assignment operators in C are some of the C Programming Operator, which are useful to assign the values to the declared variables. Let's discuss the various types of the assignment operators such as =, +=, -=, /=, *= and %=. The following table lists the assignment operators supported by the C language:
To create a program in Graphics Mode, the first step would be to include the header file graphics.h. This file is required for Graphics programming. After this, the graphics have to be initialized. C Language supports 16 Bit's MS-DOS environment. Initializing the Graphics mode is to call various functions, one such is called initgraph. initgraph initializes the graphics system by loading a graphics driver from disk (or validating a registered driver), and putting the system into graphics mode. To start the graphics system, first call the initgraph function. initgraph loads the graphics driver and puts the system into graphics mode. You can tell initgraph to use a particular graphics driver and mode, or to autodetect the attached video adapter at run time and pick the corresponding driver. If you tell initgraph to autodetect, it calls detectgraph to select a graphics driver and mode. initgraph also resets all graphics settings to their defaults (current position, palette, color, viewport, and so on)
delay() function is used to hold the program's execution for given number of milliseconds, it is declared in dos.h header file. There can be many instances when we need to create a delay in our programs. C++ provides us with an easy way to do so. We can use a delay() function for this purpose in our code. We can run the code after a specific time in C++ using delay() function.
setcolor() function is used to set the foreground color in graphics mode. After resetting the foreground color you will get the text or any other shape which you want to draw in that color. setcolor sets the current drawing color to color, which can range from 0 to getmaxcolor. The current drawing color is the value to which pixels are set when lines, and so on are drawn. The drawing colors shown below are available for the CGA and EGA, respectively.
In the C++ Programming Language, the #define directive allows the definition of macros within your source code. These macro definitions allow constant values to be declared for use throughout your code. Macro definitions are not variables and cannot be changed by your program code like variables. You generally use this syntax when creating constants that represent numbers, strings or expressions. The syntax for creating a constant using #define in the C++ is: #define token value
In computer programming, loops are used to repeat a block of code. For example, when you are displaying number from 1 to 100 you may want set the value of a variable to 1 and display it 100 times, increasing its value by 1 on each loop iteration. When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop. A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.
A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.
Compute sine. Returns the sine of an angle of x radians. sin() function is a library function of cmath header, it is used to find the sine of the given number (angle), it accepts a number (x) and returns the sine of angle x radians. Additional overloads are provided in this header (<cmath>) for the integral types: These overloads effectively cast x to a double before calculations (defined for T being any integral type). This function is also overloaded in <complex> and <valarray> (see complex sin and valarray sin).
The header file graphics.h contains setfillstyle() function which sets the current fill pattern and fill color. Current fill pattern and fill color is used to fill the area. setfillstyle sets the current fill pattern and fill color. To set a user-defined fill pattern, do not give a pattern of 12 (USER_FILL) to setfillstyle; instead, call setfillpattern.
The getch() is a predefined non-standard function that is defined in conio.h header file. It is mostly used by the Dev C/C++, MS- DOS's compilers like Turbo C to hold the screen until the user passes a single value to exit from the console screen. It can also be used to read a single byte character or string from the keyboard and then print. It does not hold any parameters. It has no buffer area to store the input character in a program. The getch() function does not accept any parameter from the user. It returns the ASCII value of the key pressed by the user as an input.
#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.
