C program to print area of triangle for vilad data

/*area of triangle for vilad data*/
#include<conio.h>
#include<stdio.h>
#include<math.h>
void main()
{
int a,b,c,s,ar;
clrscr();
printf("Enter three sides of the triangle: ");
scanf("%d%d%d",&a,&b,&c);
if((a+b>c)&&(b+c>a)&&(c+a>b))
{
s=(a+b+c)/2;
ar=sqrt(s*(s-a)*(s-b)*(s-c));
printf("\nRESULT:\nArea of triangle= %d",ar);
}
else
printf("\nRESULT:\n\nInvilid data input\nPlease inter the valid data");
getch();
}