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triangle determine

Sep 7, 2016 at 4:09am
Thephantom23 (6)
can u help me this problem :

Input :
4 3 5
output:
right triangle

input :
4 4 5
output:
isoscles triangle

input:
4 4 4
output:
equilateral triangle

can u help me for this ????/


Sep 7, 2016 at 4:16am
shadder (813)
Hi,

An effort from your side would be lovely.... could you show us what you did/tried?what problems are you facing?
Sep 7, 2016 at 6:17am
ephraimr (114)
Let three variables a,b,c be the lengths. Take this value from user. Now use some if conditions to determine the result. Where exactly is the problem?
Sep 7, 2016 at 6:18am
ephraimr (114)
Submit what you already wrote inside the code tags.
Sep 7, 2016 at 12:51pm
boost lexical cast (395)
Let's say the 3 sides are a, b, c.

Right triangle: Any of the 2 sides ([a,b], [b,c], [a,c]) squared and added equals the square of the 3rd.
Example: a^2 + b^2 = c^2 so sqrt(a^2 + b^2) = c.

Isosceles triangle: 2 of the sides are equal and one is different from the other 2.

Equilateral triangle: All of the sides are equal.

You should be able to check for these conditions easily enough.

[b]EDIT[/b]
Here's code if you don't want to do it:

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#include <iostream>
#include <cmath>
#include <conio.h> // Optional. For getch(); which pauses program
int main()
{
    int a, b, c;
    std::cout << "Enter 3 sides of triangle\n";
    std::cout << "1st side: ";
    std::cin >> a;
    std::cout << "2nd side: ";
    std::cin >> b;
    std::cout << "3rd side: ";
    std::cin >> c;
    std::cout << '\n';
    if ((a == b) && (b == c) && (a == c))
    {
        std::cout << "This triangle is an equilateral triangle\n";
    }
    if (((a == b) && ((a != c) || (b != c))) || ((a == c) && ((a != b) || (c != b))))
    {
        std::cout << "This triangle is an isosceles triangle\n";
    }
    if (((std::sqrt (a * a + b * b)) == c) || ((sqrt (b * b + c * c)) == a) || ((sqrt (a * a + c * c)) == b))
    {
        std::cout << "This triangle is a right triangle\n";
    }
    getch(); // Optional. Pauses program.
    return 0;
}
Edit & run on cpp.sh


Last edited on Sep 7, 2016 at 1:42pm
Sep 7, 2016 at 1:10pm
boost lexical cast (395)
@gentleguy

Mistake was thinking on the wrong train of thought. My code doesn't use arrays.
Sep 7, 2016 at 1:46pm
AterVulpes (60)
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            A = acos((b*b+c*c-a*a)/(2*b*c));
            B = acos((a*a+c*c-b*b)/(2*a*c));
            C = acos((a*a+b*b-c*c)/(2*a*b));


Why on Earth does this result in a 270[°] triangle O_o ? (for 3,4,5)

Whole code:

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#include <iostream>
#include <math.h>

const double M_PI = 4*atan(1);

int main()
{
    char loop;

    do
        {
        int a, b, c; //assuming whole numbers
        double A, B, C; //angles
        std::cout << "Input triangle side lengths\n";
        std::cin >> a;
        std::cin >> b;
        std::cin >> c;

        if ((a==b) & (b==c))
        {
            std::cout << "Equilateral triangle.\nAngles are: A=B=A=60[°]";
        }
        else if (((a==b) & (a!=c)) | ((a==c) & (b!=c)))
        {
            A = acos((b*b+c*c-a*a)/(2*b*c));
            B = acos((a*a+c*c-b*b)/(2*a*c));
            C = acos((a*a+b*b-c*c)/(2*a*b));

            std::cout << "Isoscles triangle. Angles are: A=" << A << "[rad] B=" << B << "[rad] C="  << C << "[rad]\n";;
        }
        else if ((a*a==b*b+c*c) | (b*b==a*a+c*c) | (c*c==a*a+b*b))
        {

            A = acos((b*b+c*c-a*a)/(2*b*c));
            B = acos((a*a+c*c-b*b)/(2*a*c));
            C = acos((a*a+b*b-c*c)/(2*a*b));

            std::cout << "Right triangle. Angles are: A=" << A << "[rad] B=" << B << "[rad] C="  << C << "[rad]\n";
        }
        else
        {
            A = acos((b*b+c*c-a*a)/(2*b*c));
            B = acos((a*a+c*c-b*b)/(2*a*c));
            C = acos((a*a+b*b-c*c)/(2*a*b));

            std::cout << "Scalene triangle.Angles are: A=" << A << "[rad] B=" << B << "[rad] C="  << C << "[rad]\n";
        }

        std::cout << "\n\nEvaluate another triangle y/n?\n";
        std::cin >> loop;
        loop = toupper(loop);
        }
        while (loop == 'Y');

    return 0;

}
Edit & run on cpp.sh
Sep 7, 2016 at 2:01pm
keskiverto (10386)
If inputs are int, then there is no need for floating-point math (e.g. acos and sqrt) and right angled isosceles triangle will not occur.
Sep 7, 2016 at 2:22pm
closed account (48T7M4Gy)
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#include <iostream>
#include <cmath>

int main()
{
    double a = 0, b = 0, c = 0;     // sides
    double aa = 0, ab = 0, ac = 0;  // angles
    double p = 0;   // perimeter
    
    std::cout << "Please enter 3 sides: ";
    std::cin >> a >> b >> c;
    
    ac = acos( (a*a + b*b - c*c)/(2*a*b) );
    aa = acos( (b*b + c*c - a*a)/(2*a*b) );
    ab = M_1_PI - ac - aa;
    
    p = a + b + c;
    
    if( aa == M_PI/2 or ab == M_PI/2 or ac == M_PI/2)
        std::cout << "Right angled triangle\n";
    else if( p / 3 == a )
        std::cout << "Equilateral triange\n";
    else if ( p - a == 2*b or p - b == 2*a or p - c == 2*a)
        std::cout << "Isosceles triangle\n";
    else
        std::cout << "Scalene triangle\n";
}
Edit & run on cpp.sh
Sep 7, 2016 at 2:59pm
JLBorges (13770)
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void swap( int& a, int& b ) { const int temp = a ; a = b ; b = temp ; }

void make_ascending( int& a, int& b ) { if( b < a ) swap(a,b) ; }

void make_ascending( int& a, int& b, int& c ) { make_ascending(a,b) ; make_ascending(b,c) ; make_ascending(a,b) ; }

bool is_side( int a ) { return a > 0 ; }

bool is_triangle( int a, int b, int c ) // a, b, c in ascending order
{ return is_side(a) && is_side(b) && is_side(c) && (a+b) > c ;  }

enum type { isosceles, equilateral, right_angled, scalene_not_right_angled, not_a_triangle = -1 };

type triangle_type( int a, int b, int c )
{
    make_ascending(a,b,c) ;

    if( is_triangle(a,b,c) )
    {
        if( a==b ) return b==c ? equilateral : isosceles ;
        else return ( a*a + b*b == c*c ) ? right_angled : scalene_not_right_angled ;
    }
    else return not_a_triangle ;
}
Sep 7, 2016 at 10:26pm
closed account (48T7M4Gy)
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#include <iostream>

int main()
{
    double a = 0, b = 0, c = 0;
    
    std::cout << "Please enter 3 sides: ";
    std::cin >> a >> b >> c;
    
    double a2 = a * a, b2 = b * b, c2 = c * c, p = a + b + c;
    
    if( a == b and b == c)
        std::cout << "Equilateral triange\n";
    else if ( p - a == 2 * b or p - b == 2 * a or p - c == 2 * a)
        std::cout << "Isosceles triangle\n";
    else if ( a2 == b2 + c2 or b2 == a2 + c2 or c2 == a2 + b2)
        std::cout << "Right angled triangle\n";
    else
        std::cout << "Scalene triangle\n";
}
Edit & run on cpp.sh
Last edited on Sep 7, 2016 at 10:29pm
Sep 8, 2016 at 8:08am
AterVulpes (60)
Topic archived. No new replies allowed.