Lokesh Kumar in C languageC SolutionChapter 6Programming

Q16 Write a function to compute the distance between two points and use it to develop another function that will compute the area of the triangle whose vertices are A(x1, y1), B(x2, y2), and C(x3, y3). Use these functions to develop a function which returns a value 1 if the point (x, y) lines inside the triangle ABC, otherwise returns a value 0.

Name: Q16 Write a function to compute the distance between two points and use it to develop another function tha ...
Uploaded: 2020-09-08T14:19:09+05:30
Channel: Lokesh Kumar
Description: Program: 137 Write a function to compute the distance between two points and use it to develop another function that

Write a function to compute the distance between two points and use it to develop another function that will compute the area of the triangle

Program: 137

Write a function to compute the distance between two points and use it to develop another function that will compute the area of the triangle whose vertices are A(x₁, y₁), B(x₂, y₂), and C(x₃, y₃). Use these functions to develop a function which returns a value 1 if the point (x, y) lines inside the triangle ABC, otherwise returns a value 0.

distance = √(x₂-x₁)²+(y₂-y₁)²)

area = √(S(S-a)(S-b)(S-c))
where, S = (a+b+c)/2.0

#include<stdio.h>
#include<math.h>
void res(float x1, float y1, float x2, float y2, float x3, float y3,
         float x, float y, float *area, int *flag);
float distance(float x1, float y1, float x2, float y2);
float cal_area(float a, float b, float c);
int position(float area, float A, float B, float C);

void main()
{
    float x1, y1, x2, y2, x3, y3, x, y;
    float area=0;
    int flag=0;

    printf("Enter the values of (x1,y1): ");
    scanf("%f%f", &x1, &y1);

    printf("Enter the values of (x2,y2): ");
    scanf("%f%f", &x2, &y2);

    printf("Enter the values of (x3,y3): ");
    scanf("%f%f", &x3, &y3);

    printf("Enter point values (x,y): ");
    scanf("%f%f", &x, &y);

    res(x1, y1, x2, y2, x3, y3, x, y, &area, &flag);

    printf("\n Area of triangle: %.2f\n", area);

    if (flag==1)
        printf("\nPoint(%.2f, %.2f) lies inside the triangle.",x,y);
    else
        printf("\nPoint(%.2f, %.2f) lies outside the triangle.",x,y);

}
void res(float x1, float y1, float x2, float y2, float x3, float y3,
         float x, float y, float *area, int *flag)
{
    float a, b, c, d, e, f, A, B, C ;

    a = distance(x1,y1,x2,y2);
    b = distance(x2,y2,x3,y3);
    c = distance(x3,y3,x1,y1);

    *area = cal_area(a,b,c);

    d = distance(x1,y1,x,y);
    e = distance(x2,y2,x,y);
    f = distance(x3,y3,x,y);

    A = cal_area(d,e,a);
    B = cal_area(e,b,f);
    C = cal_area(f,c,d);

    *flag = position(*area, A, B, C);
}

float distance(float x1, float y1, float x2, float y2)
{
    return (sqrt(pow((x2-x1),2)+pow((y2-y1),2)));
}
float cal_area(float a, float b, float c)
{
    float S,ar;

    S = (a+b+c)/2.0;

    ar = (sqrt(S*(S-a)*(S-b)*(S-c)));
    return (ar);
}
int position(float area, float A, float B, float C)
{
    float res;

    res = area-(A+B+C);

    if(res==0 || res<0.0001)
    {
        return(1);
    }
    else
    {
        return(0);
    }
}

Output:

Enter the values of (x1,y1): 1 2
Enter the values of (x2,y2): 2 4
Enter the values of (x3,y3): 3 2
Enter point values (x,y): 2 3

 Area of triangle: 2.00

Point(2.00, 3.00) lies inside the triangle.

Next Read: Q17 Write a function to compute the greatest common divisor given by Euclid's algorithm, exemplified for J=1980, K=1617 as follows: Thus, the greatest common divisor is 33. »

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Program: 137

Output:

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