#include<stdio.h>

#include<math.h>

struct DIEM

{

int x,y; 

} A,B,C;

float khoangcach(DIEM a,DIEM b)

{

return sqrt(((a.x-b.x)*(a.x-b.x))+((a.y-b.y)*(a.y-b.y))); 

}

int tamgiac(DIEM a,DIEM b,DIEM c)

{

float c1,c2,c3;

c1=khoangcach(a,b);

c2=khoangcach(b,c);

c3=khoangcach(a,c);

if(c1+c2<=c3) return 0;

if(c1+c3<=c2) return 0;

if(c3+c2<=c1) return 0; 

return 1;

}

main()

{

FILE *f;

DIEM A,B,C;

f=fopen("diem.txt","r");

if(f!=NULL)

{

fscanf(f,"%d%d",&A.x,&A.y); 

fscanf(f,"%d%d",&B.x,&B.y); 

fscanf(f,"%d%d",&C.x,&C.y); 

}

fclose(f);

f=fopen("kq.txt","w");

fprintf(f,"

toa do diem A(%d,%d)",A.x,A.y);

fprintf(f,"

toa do diem B(%d,%d)",B.x,B.y);

fprintf(f,"

toa do diem C(%d,%d)",C.x,C.y);

fprintf(f,"

khoang cach 2 diem A, B la: %f",khoangcach(A,B));

fprintf(f,"

khoang cach 2 diem C,B la: %f",khoangcach(C,B));

fprintf(f,"

khoang cach 2 diem A, C la: %f",khoangcach(A,C));

if(tamgiac(A,B,C)==1) fprintf(f,"

tao thanh 1 tam giac");

else fprintf(f,"

ko tao thanh tam giac");

fclose(f);

}