// end is the end of current expression
int calc_iter(char *code, char **end)
{
char numbuf[100];
if (code[0] != '(') {
// we are reading a number
int i = 0;
for (; code[i] && isdigit(code[i]); i++) {
numbuf[i] = code[i];
}
numbuf[i] = 0;
*end = code + i;
return atoi(numbuf);
}
int v1, v2;
char *end1, *end2;
// skip '(+ ', so code + 3
v1 = calc_iter(code+3, &end1);
// skip the space between 2 expressions
v2 = calc_iter(end1+1, &end2);
// skip ')'
*end = end2 + 1;
// see the operator
switch(code[1]) {
case '+':
return v1 + v2;
case '-':
return v1 - v2;
case '*':
return v1 * v2;
case '/':
return v1 / v2;
}
}
int main()
{
const auto xScale = (maxX - minX) / resX;
const auto yScale = (maxY - minY) / resY;
std::ofstream out("Mandelbrot.ppm");
assert(out);
out << "P3\n";
out << resX << " " << resY << "\n";
out << maxColor << "\n";
for(auto i = 0; i < resX; i++) {
for(auto j = 0; j < resY; j++) {
auto real = minX + xScale * i;
auto imag = maxY - yScale * j;
std::complex<float> c(real,imag);
Color color = calc_iter(c);
out << color.red << " " << color.green << " " << color.blue << " ";
}
out << "\n";
}
out.close();
return 0;
}
int calc(char *code)
{
char *end;
return calc_iter(code, &end);
}
