unsigned char is_inside (struct point pt, struct triangle *tri) {
int ar1, ar2, ar3, total;
struct triangle temp;
total = tri_area (tri);
if (total < 0) total *= -1;
temp.pt1 = pt;
temp.pt2 = tri->pt2;
temp.pt3 = tri->pt3;
ar1 = tri_area (&temp);
if (ar1 < 0) ar1 *= -1;
temp.pt1 = tri->pt1;
temp.pt2 = pt;
temp.pt3 = tri->pt3;
ar2 = tri_area (&temp);
if (ar2 < 0) ar2 *= -1;
temp.pt1 = tri->pt1;
temp.pt2 = tri->pt2;
temp.pt3 = pt;
ar3 = tri_area (&temp);
if (ar3 < 0) ar3 *= -1;
return ((ar1 + ar2 + ar3) <= total);
}
double trap_area(double short_side, double long_side, double height) {
//caculate the area of a trapezoid
//you can store the result of a function in a variable
//to do so just assign a variable to a function that returns something
double r_area = rect_area(short_side, height); //the area of the center square
double tri_base = (long_side - short_side) / 2.0;
double tri_areas = tri_area(tri_base, height) * 2;//the area of the triable parts
double t_area = r_area + tri_areas;
return t_area;
}
int main(int argc, char *argv[])
{
if (argc != 3) {
printf("Usage: %s <g> <h>\n", argv[0]);
return 1;
}
double g = strtod(argv[1], NULL);
double h = strtod(argv[2], NULL);
printf("area is %f\n", tri_area(g, h));
return 0;
}
void do_tri() {
double base, height, area;
printf("Please enter the base of the triangle: ");
scanf("%lf", &base);
printf("Please enter the height of the triangle: ");
scanf("%lf", &height);
area = tri_area(base, height);
printf("The area of a triangle with base %.2lf and height %.2lf is %.2lf\n", base, height, area);
}//do_tri
int main()
{
char fig[11][2];
double crd[11][6];
int i, j, k;
double x, y, d;
bool is_contained;
for(i = 1; scanf("%s", &fig[i][0]), fig[i][0] != '*'; i++)
{
if(fig[i][0]=='r')
scanf("%lf%lf%lf%lf", &crd[i][0], &crd[i][1], &crd[i][2], &crd[i][3]);
else if(fig[i][0]=='c')
scanf("%lf%lf%lf", &crd[i][0], &crd[i][1], &crd[i][2]);
else if(fig[i][0]=='t')
scanf("%lf%lf%lf%lf%lf%lf", &crd[i][0], &crd[i][1], &crd[i][2],
&crd[i][3], &crd[i][4], &crd[i][5]);
}
for(j = 1; scanf("%lf%lf", &x, &y) == 2; j++)
{
if(x==9999.9 && y==9999.9)
break;
is_contained = false;
for(k = 1; k < i; k++)
{
if(fig[k][0] == 'r')
{
if(x > crd[k][0] && x < crd[k][2] &&
y < crd[k][1] && y > crd[k][3] )
{
printf("Point %d is contained in figure %d\n", j, k);
is_contained = true;
}
}
else if(fig[k][0] == 'c')
{
d = sqrt(pow((x - crd[k][0]), 2.0) + pow((y - crd[k][1]), 2.0));
if(d < crd[k][2])
{
printf("Point %d is contained in figure %d\n", j, k);
is_contained = true;
}
}
else if(fig[k][0] == 't')
{
double t, t1, t2, t3;
t1 = tri_area(crd[k][0], crd[k][1], crd[k][2], crd[k][3], x, y);
t2 = tri_area(crd[k][2], crd[k][3], crd[k][4], crd[k][5], x, y);
t3 = tri_area(crd[k][0], crd[k][1], crd[k][4], crd[k][5], x, y);
t = tri_area(crd[k][0], crd[k][1], crd[k][2], crd[k][3], crd[k][4], crd[k][5]);
if(t1 != 0 && t2 != 0 && t3 != 0 && (fabs((t1 + t2 + t3) - t) < 1e-6))
{
printf("Point %d is contained in figure %d\n", j, k);
is_contained = true;
}
}
}
if(is_contained == false)
printf("Point %d is not contained in any figure\n", j);
}
return 0;
}
