Thread: functions problem (help)

i am trying to training my self to use functions and i start with easy tasks but i though that this task will work but the output is not show any result any idea why ?



this is the task ....










my code

Code:

#include<stdio.h>
#include<math.h>
#define PI 3.14
double deg_to_radians (double t);
double length_third_side (double n1,double n2,double tr);
double calculateArea(double s,double n1,double n2, double n3 );


int main ()
{
    
    double n1,n2,n3,r,t,tr,s,a;
    printf("Enter the length of side 1 [cm] :\n" );
    scanf("%lf",&n1);
    printf("Enter the length of side 2 [cm] :\n");
    scanf("%lf",&n2);
    printf("Enter the angel in degrees bettween side1 and side 2:");
    scanf("%lf",&t);
    tr= deg_to_radians (t);
    n3= length_third_side (n1,n2,tr);
    s=(n1+n2+n2)/2.0;
    a= calculateArea(s,n1,n2,n3);
    
    printf ("The area of the triangle = %.2lf ",a);
    return 0;
    
}


double deg_to_radians (double t){
    double tr ;
    
    tr = t*PI/180.0;
    return tr;
}
double length_third_side (double n1,double n2,double tr){
    double n3;
    n3 =n1*n1*n2*n2-(2*n1*n2*cos(tr));
    return n3;
}
double calculateArea(double s,double n1,double n2, double n3 ){
    double a;
    a=sqrt(s*(s-n3)*(s-n1)*(s-n2));
    return a ; 


}

Presumably s should involve n1, n2, and n3, rather than n1, n2, and n2.

i fixed it but till the same


---------- turned out that the problem is i define a^2 not a so i just need to put a sqrt

I can only assume where the mistake is in your program.
The function deg_to_radians is not correct, the formula is:
((2 * PI) / 360) * winkel.
For the computation of the third side you should use the pow-function -- maybe is there also a mistake in the program.


This program run correct:

Code:

#include <stdlib.h>
#include <stdio.h>
#include <math.h>


#define PI 3.14159


//Deklaration
double gradmass_in_bogenmass(double winkelgrad);
double dreieck_dritte_seite(double a, double b, double radiant);
double flaeche_dreieck(double a, double b, double c);


int main(void)
{
    double a, b, winkel;     
    
    system("cls");
    printf("\nBerechnung des Flaecheninhalts eines beliebigen Dreiecks\n\n");
    
    printf("Geben Sie die Laenge des Dreiecks von Seite a ein: ");
    scanf("%lf", &a);
    printf("Geben Sie die Laenge des Dreiecks von Seite b ein: ");
    scanf("%lf", &b);
    printf("Geben Sie den Winkel zwischen a und b ein        : ");
    scanf("%lf", &winkel);
    
    printf("\nDas Bogenmass betraegt           : %6.2lf rad", gradmass_in_bogenmass(winkel));
    printf("\nDie Laenge von Seite c betraegt  : %6.2lf cm", dreieck_dritte_seite(a, b, gradmass_in_bogenmass(winkel)));
    printf("\nDie Flaeche des Dreiecks betraegt: %6.2lf qcm\n", flaeche_dreieck(a, b, 
                                                         dreieck_dritte_seite(a, b, gradmass_in_bogenmass(winkel))));
    
    return(0);
}


double gradmass_in_bogenmass(double winkelgrad)
{
    double radiant;
    
    radiant = (((2 * PI) / 360) * winkelgrad);
    return radiant;
}


double dreieck_dritte_seite(double a, double b, double radiant)
{
    double y = 2.0;  //Hilfsvariable
    double seite_c;
    
    seite_c = sqrt((pow(a, y) + pow(b, y)) - (2 * a * b * cos(radiant)));
    return seite_c;
}


double flaeche_dreieck(double a, double b, double c)
{
    double S, flaeche;
    
    S = ((a + b + c) / 2);
    flaeche = sqrt((S * ((S - a) * (S - b) * (S - c))));
    return flaeche;
}