### 2. 2D Rotation Program Using C Programming

 `#include``#include``#include``#include``#include`` `` ``void TriAngle(int x1,int y1,int x2,int y2,int x3,int y3);``void Rotate(int x1,int y1,int x2,int y2,int x3,int y3);`` `` ``void main()``{``    int gd=DETECT,gm;``    int x1,y1,x2,y2,x3,y3;                                       ``    initgraph(&gd,&gm," ");`` `` ``    printf("Enter the 1st point for the triangle:");``    scanf("%d%d",&x1,&y1);``    printf("Enter the 2nd point for the triangle:");``    scanf("%d%d",&x2,&y2);``    printf("Enter the 3rd point for the triangle:");``    scanf("%d%d",&x3,&y3);``    TriAngle(x1,y1,x2,y2,x3,y3);``    getch();``    cleardevice();``    Rotate(x1,y1,x2,y2,x3,y3);``     setcolor(1);``    TriAngle(x1,y1,x2,y2,x3,y3);``    getch();``}`` ```` ````void TriAngle(int x1,int y1,int x2,int y2,int x3,int y3)``{``   line(x1,y1,x2,y2);``   line(x2,y2,x3,y3);``   line(x3,y3,x1,y1);``}`` ``void Rotate(int x1,int y1,int x2,int y2,int x3,int y3)``{``    int x,y,a1,b1,a2,b2,a3,b3,p=x2,q=y2;``    float Angle;``    printf("Enter the angle for rotation:");``    scanf("%f",&Angle);``    cleardevice();``    Angle=(Angle*3.14)/180;``    a1=p+(x1-p)*cos(Angle)-(y1-q)*sin(Angle);``    b1=q+(x1-p)*sin(Angle)+(y1-q)*cos(Angle);``    a2=p+(x2-p)*cos(Angle)-(y2-q)*sin(Angle);``    b2=q+(x2-p)*sin(Angle)+(y2-q)*cos(Angle);``    a3=p+(x3-p)*cos(Angle)-(y3-q)*sin(Angle);``    b3=q+(x3-p)*sin(Angle)+(y3-q)*cos(Angle);``     printf("Rotate");``    TriAngle(a1,b1,a2,b2,a3,b3);``}`