trig calculator

just finished my first program which is actually usefull to me.
It just figures out right angle triangles

Code:

#include <stdio.h>
#include <string>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <fstream>
using namespace std;
void welcome();
float decision(string);
float sides(float &, float &, float &, float &, float &);
int main(int argc, char *argv[])
{
welcome();

  return 0;
}
void welcome(){
int menu;
float valuea;
float valueb;
float valuec;
float valueao;
float valuebo;
float valueco;
cout << "Trig Calculator" << endl << endl;
cout << "Select problem type\n1. Right angle triangle" << endl;
cin >> menu;
switch(menu){
case 1:

 cout << "If you do not know the value use 0.\n\n";
 valuea = decision("Do you know side A?\n");
 valueb = decision("Do you know side B?\n");
 valuec = decision("Do you know side C?\n");
 valueao = decision("Do you know angle A?\n");
 valuebo = decision("Do you know angle B?\n");
 sides(valuea, valueb, valuec, valueao, valuebo);
 cout << "\n\nTriangle calculated:\n\n";
 cout << "Side A: " << valuea << endl;
 cout << "Side B: " << valueb << endl;
 cout << "Side C: " << valuec << endl;
 cout << "Angle A: " << valueao << endl;
 cout << "Angle B: " << valuebo << endl << endl;
 welcome();
 }

}
float decision(string question){
float value;
float radian = 3.1415/180;
cout << question;
cin >> value;
return value;
}
float sides(float &a, float &b, float &c, float &ao, float &bo){
float radian = 3.1415/180;
if(a !=0 && b!=0 && c==0){
c = sqrt(a * a + b * b);
}
if(a !=0 && c!=0 && b==0){
b = sqrt(c * c - a * a);
}
if(a ==0 && c!=0 && b!=0){
a = sqrt(c * c - b * b);
}
//TAN with side A
if(a!= 0 && b==0 && c==0){
if(ao !=0){
b = a/tan(ao*radian);
if(bo == 0){
bo = 90-ao;
}
}
if(bo !=0){
b = a*tan(bo*radian);
if(ao == 0){
ao = 90-bo;
}
}
c = sqrt((a*a)+(b*b));
}
//tan with sideB
if(a == 0 && b!=0 && c==0){
if(ao !=0){
a = b*tan(bo*radian);
if(bo == 0){
bo = 90-ao;
}
}
if(bo !=0){
a = b/tan(bo*radian);
if(ao == 0){
ao = 90-bo;
}
}
c = sqrt((a*a)+(b*b));
}
//sin with sideC
if(a == 0 && b==0 && c!=0){
if(ao !=0){
a = c*sin(ao*radian);
if(bo == 0){
bo = 90-ao;
}
}
if(bo !=0){
a = c*cos(bo*radian);
if(ao == 0){
ao = 90-bo;
}
}
b = sqrt((c*c)+(a*a));
}
if(ao == 0 && bo ==0){
ao = atan(a/b)*180/3.141592654;
bo = 90 - ao;
}
}

keep in mind I started using c++ only a few days ago. Any sugestions?

Well, this is your main() function:

Code:

int main(int argc, char *argv[])
{
welcome();

  return 0;
}

which should be the main hub of activity, but it looks like a ghost town. I would get rid of your welcome() function and move all that code into main().

It looks like your switch statement has one case--that means it's just an if statement.

The recursive welcome() function call in your switch statement is not a very elegant construct. You should consider using a while loop that terminates when you enter a certain number.

If you can get more than 10 lines to compile when you are first starting--much less produce correct output-- you are way ahead of the game.

You could try learning some indentation techniques while you're at it.

Originally Posted by Salem

You could try learning some indentation techniques while you're at it.

I second that notion.

edit: I indented your code for you, and all I have to say is, find a better way... use less variables, clean up your conditional statements, and get rid of the case in void welcome() (which should just be the code in main():

Code:

void welcome()
{
    int menu;
    float valuea;
    float valueb;
    float valuec;
    float valueao;
    float valuebo;
    float valueco;
    
    for(;;)
        cout << "Trig Calculator" << endl << endl;
        cout << "Select problem type\n1. Right angle triangle" << endl;
        cin >> menu;
        
        if(menu==1)
            break;
        
        cout << "If you do not know the value use 0.\n\n";
        valuea = decision("Do you know side A?\n");
        valueb = decision("Do you know side B?\n");
        valuec = decision("Do you know side C?\n");
        valueao = decision("Do you know angle A?\n");
        valuebo = decision("Do you know angle B?\n");
        
        sides(valuea, valueb, valuec, valueao, valuebo);
        
        cout << "\n\nTriangle calculated:\n\n";
        cout << "Side A: " << valuea << endl;
        cout << "Side B: " << valueb << endl;
        cout << "Side C: " << valuec << endl;
        cout << "Angle A: " << valueao << endl;
        cout << "Angle B: " << valuebo << endl << endl;
    }
}

and the rest of your indented code (your original, untouched code)

Code:

#include <stdio.h>
#include <string>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <fstream>


using namespace std;

void welcome();
float decision(string);
float sides(float &, float &, float &, float &, float &);

int main(int argc, char *argv[])
{
        welcome();
        return 0;
}

void welcome()
{
    int menu;
    float valuea;
    float valueb;
    float valuec;
    float valueao;
    float valuebo;
    float valueco;
    
    cout << "Trig Calculator" << endl << endl;
    cout << "Select problem type\n1. Right angle triangle" << endl;
    cin >> menu;
    
    switch(menu)
    {
        case 1:
             cout << "If you do not know the value use 0.\n\n";
             valuea = decision("Do you know side A?\n");
             valueb = decision("Do you know side B?\n");
             valuec = decision("Do you know side C?\n");
             valueao = decision("Do you know angle A?\n");
             valuebo = decision("Do you know angle B?\n");
             sides(valuea, valueb, valuec, valueao, valuebo);
             cout << "\n\nTriangle calculated:\n\n";
             cout << "Side A: " << valuea << endl;
             cout << "Side B: " << valueb << endl;
             cout << "Side C: " << valuec << endl;
             cout << "Angle A: " << valueao << endl;
             cout << "Angle B: " << valuebo << endl << endl;
             welcome();
     }

}

float decision(string question)
{
    float value;
    float radian = 3.1415/180;
    
    cout << question;
    cin >> value;
    
    return value;
}

float sides(float &a, float &b, float &c, float &ao, float &bo)
{
    float radian = 3.1415/180;
    if(a !=0 && b!=0 && c==0)
    {
        c = sqrt(a * a + b * b);
    }
    if(a !=0 && c!=0 && b==0)
    {
        b = sqrt(c * c - a * a);
    }
    if(a ==0 && c!=0 && b!=0)
    {
    a = sqrt(c * c - b * b);
    }
    //TAN with side A
    if(a!= 0 && b==0 && c==0)
    {
        if(ao !=0)
        {
            b = a/tan(ao*radian);
            if(bo == 0)
            {
                bo = 90-ao;
            }
        }
        if(bo !=0)
        {
            b = a*tan(bo*radian);
                if(ao == 0)
                {
                    ao = 90-bo;
                }
        }
        c = sqrt((a*a)+(b*b));
    }
    //tan with sideB
    if(a == 0 && b!=0 && c==0)
    {
        if(ao !=0)
        {
            a = b*tan(bo*radian);
            if(bo == 0)
            {
                bo = 90-ao;
            }
        }
        if(bo !=0)
        {
            a = b/tan(bo*radian);
            if(ao == 0)
            {
                ao = 90-bo;
            }
        }
        c = sqrt((a*a)+(b*b));
    }
    //sin with sideC
    if(a == 0 && b==0 && c!=0)
    {
        if(ao !=0)
        {
            a = c*sin(ao*radian);
            if(bo == 0)
            {
                bo = 90-ao;
            }
        }
        if(bo !=0)
        {
            a = c*cos(bo*radian);
            if(ao == 0)
            {
                ao = 90-bo;
            }
        }
        b = sqrt((c*c)+(a*a));
    }
    if(ao == 0 && bo ==0)
    {
        ao = atan(a/b)*180/3.141592654;
        bo = 90 - ao;
    }
}

I just noticed this:

Code:

float radian = 3.1415/180;

Code:

ao = atan(a/b)*180/3.141592654;

please, for the sake of sanity, consider using a constant here, a simple line of code would save you a world of confusion:

Code:

const double pi=31.141592654;

Pi ~ 31, eh?

lol, i think he might've meant:

const double pi=3.141592654;

but if 31 is what he wanted.....

yeah, I actually meant 31,415,926.54

Hmm... I see a problem if Side C == 0, and either Angle A or B == 0. Then it will never calculate Angle A or B!..
Or am I totally wrong?

yea, but that's an unlikely situation. I wrote it mostly for when I'm doing physics stuff on the computer and don't want to use windows calc

Yes, it's very unlikely, but I just fought of it.
If you had to publish your work some day, and a person switched between the letters, so that the 90degree angle would be B instead of C. Then you would have a problem. But if it's for home use only, then it would do with the 3 if-sentences alone