const float theta_spacing = 0.07; const float phi_spacing = 0.02; const float R1 = 1; const float R2 = 2; const float K2 = 5; // Calculate K1 based on screen size: the maximum x-distance occurs // roughly at the edge of the torus, which is at x=R1+R2, z=0. we // want that to be displaced 3/8ths of the width of the screen, which // is 3/4th of the way from the center to the side of the screen. // screen_width*3/8 = K1*(R1+R2)/(K2+0) // screen_width*K2*3/(8*(R1+R2)) = K1 const float K1 = screen_width*K2*3/(8*(R1+R2)); render_frame(float A, float B) { // precompute sines and cosines of A and B float cosA = cos(A), sinA = sin(A); float cosB = cos(B), sinB = sin(B); char output[0..screen_width, 0..screen_height] = ' '; float zbuffer[0..screen_width, 0..screen_height] = 0; // theta goes around the cross-sectional circle of a torus for (float theta=0; theta < 2*pi; theta += theta_spacing) { // precompute sines and cosines of theta float costheta = cos(theta), sintheta = sin(theta); // phi goes around the center of revolution of a torus for(float phi=0; phi < 2*pi; phi += phi_spacing) { // precompute sines and cosines of phi float cosphi = cos(phi), sinphi = sin(phi); // the x,y coordinate of the circle, before revolving (factored // out of the above equations) float circlex = R2 + R1*costheta; float circley = R1*sintheta; // final 3D (x,y,z) coordinate after rotations, directly from // our math above float x = circlex*(cosB*cosphi + sinA*sinB*sinphi) - circley*cosA*sinB; float y = circlex*(sinB*cosphi - sinA*cosB*sinphi) + circley*cosA*cosB; float z = K2 + cosA*circlex*sinphi + circley*sinA; float ooz = 1/z; // "one over z" // x and y projection. note that y is negated here, because y // goes up in 3D space but down on 2D displays. int xp = (int) (screen_width/2 + K1*ooz*x); int yp = (int) (screen_height/2 - K1*ooz*y); // calculate luminance. ugly, but correct. float L = cosphi*costheta*sinB - cosA*costheta*sinphi - sinA*sintheta + cosB*(cosA*sintheta - costheta*sinA*sinphi); // L ranges from -sqrt(2) to +sqrt(2). If it's < 0, the surface // is pointing away from us, so we won't bother trying to plot it. if (L > 0) { // test against the z-buffer. larger 1/z means the pixel is // closer to the viewer than what's already plotted. if(ooz > zbuffer[xp,yp]) { zbuffer[xp, yp] = ooz; int luminance_index = L*8; // luminance_index is now in the range 0..11 (8*sqrt(2) = 11.3) // now we lookup the character corresponding to the // luminance and plot it in our output: output[xp, yp] = ".,-~:;=!*#$@"[luminance_index]; } } } } // now, dump output[] to the screen. // bring cursor to "home" location, in just about any currently-used // terminal emulation mode printf("\x1b[H"); for (int j = 0; j < screen_height; j++) { for (int i = 0; i < screen_width; i++) { putchar(output[i,j]); } putchar('\n'); } }
Write, Run & Share C Language code online using OneCompiler's C online compiler for free. It's one of the robust, feature-rich online compilers for C language, running the latest C version which is C18. Getting started with the OneCompiler's C editor is really simple and pretty fast. The editor shows sample boilerplate code when you choose language as 'C' and start coding!
OneCompiler's C online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample C program which takes name as input and print your name with hello.
#include <stdio.h>
int main()
{
char name[50];
printf("Enter name:");
scanf("%s", name);
printf("Hello %s \n" , name );
return 0;
}
C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.
When ever you want to perform a set of operations based on a condition if-else
is used.
if(conditional-expression) {
// code
} else {
// code
}
You can also use if-else for nested Ifs and if-else-if ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to if-else-if ladder.
switch(conditional-expression) {
case value1:
// code
break; // optional
case value2:
// code
break; // optional
...
default:
// code to be executed when all the above cases are not matched;
}
For loop is used to iterate a set of statements based on a condition.
for(Initialization; Condition; Increment/decrement){
// code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while(condition) {
// code
}
Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.
do {
// code
} while (condition);
Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.
data-type array-name[size];
data-type array-name[size][size];
Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity.
Two types of functions are present in C
Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,
User defined functions are the ones which are written by the programmer based on the requirement.
return_type function_name(parameters);
function_name (parameters)
return_type function_name(parameters) {
//code
}