//switch结构//Edge------[NWPU][2018寒假作业][通用版]一C题

For products that are wrapped in small packings it is necessary that the sheet of paper containing the directions for use is folded until its size becomes small enough. We assume that a sheet of paper is rectangular and only folded along lines parallel to its initially shorter edge. The act of folding along such a line, however, can be performed in two directions: either the surface on the top of the sheet is brought together, or the surface on its bottom. In both cases the two parts of the rectangle that are separated by the folding line are laid together neatly and we ignore any differences in thickness of the resulting folded sheet.

After several such folding steps have been performed we may unfold the sheet again and take a look at its longer edge holding the sheet so that it appears as a one-dimensional curve, actually a concatenation of line segments. If we move along this curve in a fixed direction we can classify every place where the sheet was folded as either type A meaning a clockwise turn or type V meaning a counter-clockwise turn. Given such a sequence of classifications, produce a drawing of the longer edge of the sheet assuming 90 degree turns at equidistant places.

Input

The input contains several test cases, each on a separate line. Each line contains a nonempty string of characters A and V describing the longer edge of the sheet. You may assume that the length of the string is less than 200. The input file terminates immediately after the last test case.

Output

For each test case generate a PostScript drawing of the edge with commands placed on separate lines. Start every drawing at the coordinates (300, 420) with the command “300 420 moveto”. The first turn occurs at (310, 420) using the command “310 420 lineto”. Continue with clockwise or counter-clockwise turns according to the input string, using a sequence of “x y lineto” commands with the appropriate coordinates. The turning points are separated at a distance of 10 units. Do not forget the end point of the edge and finish each test case by the commands stroke and showpage.

You may display such drawings with the gv PostScript interpreter, optionally after a conversion using the ps2ps utility.

Sample Input

V

AVV

Sample Output

300 420 moveto

310 420 lineto

310 430 lineto

stroke

showpage

300 420 moveto

310 420 lineto

310 410 lineto

320 410 lineto

320 420 lineto

stroke

showpage

解题思路：

这道题题目很长，但前面讲的一大段都没用，其实就是一段线段以不同端点做顺时针、逆时针旋转。

用switch结构就可以解决，需要讨论顺逆时针和旋转中心点在线段哪一侧。

这种题需要，先画个图把过程想清楚。

#include<stdio.h>
#include<string.h>

int main()
{
char dire[201];
char flag;
int len,i,x,y;
while(scanf("%s",dire)!=EOF)
{
len=strlen(dire);
flag='r';//最初的线段是延x轴正方向走的
x=310;
y=420;
printf("300 420 moveto\n310 420 lineto\n");
for(i=0;i<len;i++)
{
switch(flag)
{
case 'r': //r为x轴正方向,旋转点在右侧
if(dire[i]=='A')
{
y=y-10;
flag='d';
}
else
{
y=y+10;
flag='u';
}
break;
case 'd': //d为y轴负方向，旋转点在下侧
if(dire[i]=='A')
{
x=x-10;
flag='l';
}
else
{
x=x+10;
flag='r';
}
break;
case 'l': //l为x轴负方向，旋转点在左侧
if(dire[i]=='A')
{
y=y+10;
flag='u';
}
else
{
y=y-10;
flag='d';
}
break;
case 'u': //u为y轴正方向，旋转点在上侧
if(dire[i]=='A')
{
x=x+10;
flag='r';
}
else
{
x=x-10;
flag='l';
}
break;
}
printf("%d %d lineto\n",x,y);
}
printf("stroke\nshowpage\n");
}
}