UVa 477 - Points in Figures: Rectangles and Circles

Problem link

Keyword: geometry

Algorithm:

Record all shapes and check if each point is in a certain shape or not.
Take care of precision error.

Code:

#include<cstdio>
#include<cmath>
const double eps = 1e-12, end = 9999.9;
struct Rectangle
{
    double ulx, uly, drx, dry;
} rec[ 1000 ];
struct Circle
{
    double rx, ry, radius;
} cir[ 1000 ];

int main()
{
    char type, all[ 2000 ] = { 0 };
    int r = 0, c = 0, a = 0, point = 0;
    double x, y;

    while( scanf( "%c", &type ) && type != '*' )
        if( type == 'r' && ( all[ a++ ] = type ) )
            scanf( "%lf %lf %lf %lf\n", &rec[ r ].ulx, &rec[ r ].uly, &rec[ r ].drx, &rec[ r ].dry ), ++r;
        else if( all[ a++ ] = type )
            scanf( "%lf %lf %lf\n", &cir[ c ].rx, &cir[ c ].ry, &cir[ c ].radius ), ++c;
    while( scanf( "%lf %lf", &x, &y ) && std::abs( x-end ) > eps && std::abs( y-end ) > eps )
    {
        bool out = false;
        int tmpr = 0, tmpc = 0;
        ++point;
        for( int i = 0; i < a; ++i )
        {
            if( all[ i ] == 'r' )
            {
                if( x > rec[ tmpr ].ulx && x < rec[ tmpr ].drx && y < rec[ tmpr ].uly && y > rec[ tmpr ].dry ) 
                    printf( "Point %d is contained in figure %d\n", point, i+1 ), out = true;
                ++tmpr;
            }
            else if( all[ i ] == 'c' )
            {
                if( hypot( x-cir[ tmpc ].rx, y-cir[ tmpc ].ry ) - cir[ tmpc ].radius < eps )
                    printf( "Point %d is contained in figure %d\n", point, i+1 ), out = true;
                ++tmpc;
            }
        }
        if( !out )
            printf( "Point %d is not contained in any figure\n", point );
    }

    return 0;
}