Why is my calculator not responding to my if statements? - c++

Question

Newbie programmer here. I'm finished with this project I was working on, and all of my if and else statements function properly, but only when they are placed at the very top of the code I'm writing.
For example, I started writing this code from if(number == 1) and worked my way down, but I eventually had to cut and paste them at the top, because when I entered a value that wasn't 1 (the first if statement, and thus the top statement that functions), the calculator failed to print anything at all when inputting a value for anything else except the top one. Because 4 is at the top, it works fine, but 1-3 don't work, and if I was to put 1 at the top then 2-4 would not print anything.
Here is a screeshot of the if statements on the bottom that do not print, and also have no debugging signs:
I'm sure it's a small issue that I managed to turn big.
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
int number;
float area1, area2, area3, area4;
int R1;
int trib;
int trih;
int top;
int bott;
int traph;
int majxis;
int minxis;
const float PI= 3.14159;
cout<< "I'm starting my program ";
cout<<"\n1.Circle";
cout<<"\n2.triangle";
cout<<"\n3.trapezoid";
cout<<"\n4.ellipse ";
cout<<"\nEnter the corresponding number of your choice(1-4):";
cin>> number;
if(number <= 0)
{
cout<<"Integer is invalid, try again ";
cin>> number;
}
if(number == 4)
{
cout<<"\nWhat is the length of the semi-major axis of the ellipse? ";
}
cin>> majxis;
if(majxis <=0)
{
cout<<"Invalid value for the semi-major axis, try again: ";
}
else
{
cout<<"What is the length for the semi-minor axis of the ellipse? ";
}
cin>> minxis;
area4= PI*minxis*majxis;
if(minxis <=0)
{
cout<<"Invalid value for the semi-minor axis, try again: ";
}
else
{
cout<<"The area of an ellipse with a semi-major axis of " << majxis<< "and a semi-minor axis of " << minxis << "is " << area4;
}
if(number == 3)
{
cout<<"\nWhat is the length of the top of the trapezoid? ";
}
cin>> top;
if(top <=0 )
{
cout<<"\n Invalid value for top length of trapezoid, try again";
}
else
{
cout<<"\nWhat is the length of the bottom of the trapezoid? ";
}
cin>> bott;
if (bott <= 0)
{
cout<<"Invalid value for bottom length of trapezoid, try again: ";
}
else
{
cout<<"What is the height of the trapezoid? ";
}
cin>>traph;
area3 = (top+bott)*0.5+traph;
if (traph <= 0)
{
cout<<"Invalid value for height of trapezoid";
}
else
{
cout<<"The area of a trapezoid with a bottom of " << bott << "and a top of " << top << "is " << area3;
}
if(number == 2)
{
cout<<"\nWhat is the length of the base of the triangle?";
}
cin>> trib;
if(trib<=0)
{
cout<<"\nInvalid Base of triangle, try again:";
}
else
{
cout<<"\nWhat is the height of the triangle? ";
}
cin>> trih;
area2 = (0.5*trib)*trih;
if(trih<=0)
{
cout<<"\nInvalid height of triangle, try again:";
}
else
{
cout<<"\nThe area of a trangle with a base of " << trib << "and a height of "<< trih <<" is " << area2;
}
if(number == 1)
{
cout<<"\nWhat is the radius of the circle?";
}
cin>> R1;
area1 = PI*(R1 *R1);
if( R1 <=0)
{cout<<"\nRadius must be greater than 0, try again";
cin>> R1;
}
else
{
cout<< "\nThe area of a circle with a radius of " << R1 << " is" << area1;
}
}

Answer 1

It indeed is a small issue. Here is the correct program:
#include <iostream>
#include <iomanip>
int main()
{
int number;
float area1, area2, area3, area4;
int R1;
int trib;
int trih;
int top;
int bott;
int traph;
int majxis;
int minxis;
const float PI = 3.14159;
std::cout << "I'm starting my program ";
std::cout << "\n1.Circle";
std::cout << "\n2.triangle";
std::cout << "\n3.trapezoid";
std::cout << "\n4.ellipse ";
std::cout << "\nEnter the corresponding number of your choice(1-4):";
std::cin >> number;
if (number <= 0)
{
std::cout << "Integer is invalid, try again ";
std::cin >> number;
}
else if (number == 1)
{
std::cout << "\nWhat is the radius of the circle?";
std::cin >> R1;
area1 = PI * (R1 * R1);
if (R1 <= 0)
{
std::cout << "\nRadius must be greater than 0, try again";
std::cin >> R1;
}
else
{
std::cout << "\nThe area of a circle with a radius of " << R1 << " is" << area1;
}
}
else if (number == 2)
{
std::cout << "\nWhat is the length of the base of the triangle?";
std::cin >> trib;
if (trib <= 0)
{
std::cout << "\nInvalid Base of triangle, try again:";
}
else
{
std::cout << "\nWhat is the height of the triangle? ";
}
std::cin >> trih;
area2 = (0.5 * trib) * trih;
if (trih <= 0)
{
std::cout << "\nInvalid height of triangle, try again:";
}
else
{
std::cout << "\nThe area of a trangle with a base of " << trib << "and a height of " << trih << " is " << area2;
}
}
else if (number == 3)
{
std::cout << "\nWhat is the length of the top of the trapezoid? ";
std::cin >> top;
if (top <= 0)
{
std::cout << "\n Invalid value for top length of trapezoid, try again";
}
else
{
std::cout << "\nWhat is the length of the bottom of the trapezoid? ";
}
std::cin >> bott;
if (bott <= 0)
{
std::cout << "Invalid value for bottom length of trapezoid, try again: ";
}
else
{
std::cout << "What is the height of the trapezoid? ";
}
std::cin >> traph;
area3 = (top + bott) * 0.5 + traph;
if (traph <= 0)
{
std::cout << "Invalid value for height of trapezoid";
}
else
{
std::cout << "The area of a trapezoid with a bottom of " << bott << "and a top of " << top << "is " << area3;
}
}
else if (number == 4)
{
std::cout << "\nWhat is the length of the semi-major axis of the ellipse? ";
std::cin >> majxis;
if (majxis <= 0)
{
std::cout << "Invalid value for the semi-major axis, try again: ";
}
else
{
std::cout << "What is the length for the semi-minor axis of the ellipse? ";
}
std::cin >> minxis;
area4 = PI * minxis * majxis;
if (minxis <= 0)
{
std::cout << "Invalid value for the semi-minor axis, try again: ";
}
else
{
std::cout << "The area of an ellipse with a semi-major axis of " << majxis << "and a semi-minor axis of " << minxis << "is " << area4;
}
}
}
Explanation: Let's take an example of the area of eclipse (number == 4). In your code, you have made the following if condition:
if(number == 4)
{
cout<<"\nWhat is the length of the semi-major axis of the ellipse? ";
}
This means if number == 4 then print - "\nWhat is the length of the semi-major axis of the ellipse? " but all of the code after it is outside the if condition's {} brackets, and thus is not considered as a part of the if statement. It will be called anyways even if number != 4. Now, in my code, I've done this:
else if (number == 4)
{
std::cout << "\nWhat is the length of the semi-major axis of the ellipse? ";
std::cin >> majxis;
if (majxis <= 0)
{
std::cout << "Invalid value for the semi-major axis, try again: ";
}
else
{
std::cout << "What is the length for the semi-minor axis of the ellipse? ";
}
std::cin >> minxis;
area4 = PI * minxis * majxis;
if (minxis <= 0)
{
std::cout << "Invalid value for the semi-minor axis, try again: ";
}
else
{
std::cout << "The area of an ellipse with a semi-major axis of " << majxis << "and a semi-minor axis of " << minxis << "is " << area4;
}
}
Here, all of the code related to the area of the eclipse is all part of the if (number == 4) statement because it is present between the brackets {} of the if (number == 4) statement.
Apply this to all 4 cases and you get the correct program.
Also, it would be better to refactor your code as such:
#include <iostream>
#include <iomanip>
const float PI = 3.14159;
void areaof_circle()
{
float area;
int R1;
std::cout << "\nWhat is the radius of the circle?";
std::cin >> R1;
area = PI * (R1 * R1);
if (R1 <= 0)
{
std::cout << "\nRadius must be greater than 0, try again";
std::cin >> R1;
}
else
{
std::cout << "\nThe area of a circle with a radius of " << R1 << " is" << area;
}
}
void areaof_triangle()
{
float area;
int trib, trih;
std::cout << "\nWhat is the length of the base of the triangle?";
std::cin >> trib;
if (trib <= 0)
{
std::cout << "\nInvalid Base of triangle, try again:";
}
else
{
std::cout << "\nWhat is the height of the triangle? ";
}
std::cin >> trih;
area = (0.5 * trib) * trih;
if (trih <= 0)
{
std::cout << "\nInvalid height of triangle, try again:";
}
else
{
std::cout << "\nThe area of a trangle with a base of " << trib << "and a height of " << trih << " is " << area;
}
}
void areaof_trapezoid()
{
float area;
int top, bott, traph;
std::cout << "\nWhat is the length of the top of the trapezoid? ";
std::cin >> top;
if (top <= 0)
{
std::cout << "\n Invalid value for top length of trapezoid, try again";
}
else
{
std::cout << "\nWhat is the length of the bottom of the trapezoid? ";
}
std::cin >> bott;
if (bott <= 0)
{
std::cout << "Invalid value for bottom length of trapezoid, try again: ";
}
else
{
std::cout << "What is the height of the trapezoid? ";
}
std::cin >> traph;
area = (top + bott) * 0.5 + traph;
if (traph <= 0)
{
std::cout << "Invalid value for height of trapezoid";
}
else
{
std::cout << "The area of a trapezoid with a bottom of " << bott << "and a top of " << top << "is " << area;
}
}
void areaof_ellipse()
{
float area;
int majxis, minxis;
std::cout << "\nWhat is the length of the semi-major axis of the ellipse? ";
std::cin >> majxis;
if (majxis <= 0)
{
std::cout << "Invalid value for the semi-major axis, try again: ";
}
else
{
std::cout << "What is the length for the semi-minor axis of the ellipse? ";
}
std::cin >> minxis;
area = PI * minxis * majxis;
if (minxis <= 0)
{
std::cout << "Invalid value for the semi-minor axis, try again: ";
}
else
{
std::cout << "The area of an ellipse with a semi-major axis of " << majxis << "and a semi-minor axis of " << minxis << "is " << area;
}
}
int main()
{
int number;
const float PI = 3.14159;
std::cout << "I'm starting my program ";
std::cout << "\n1.Circle";
std::cout << "\n2.triangle";
std::cout << "\n3.trapezoid";
std::cout << "\n4.ellipse ";
std::cout << "\nEnter the corresponding number of your choice(1-4):";
std::cin >> number;
if (number <= 0)
{
std::cout << "Integer is invalid, try again ";
std::cin >> number;
}
else if (number == 1)
{
areaof_circle();
}
else if (number == 2)
{
areaof_triangle();
}
else if (number == 3)
{
areaof_trapezoid();
}
else if (number == 4)
{
areaof_ellipse();
}
}
Also, don't use the following in your programs:
using namespace std;
...as it's considered as bad practice. Use std:: every time instead.

Answer 2

There is a problem with your if statement..
as the well defined answer is already given, I am simplifying your code's readability and suggesting more better way to do this..
NOTE: Considering you're new bie.
Create Functions to handle different quadrilaterals
#include <iostream>
#include <iomanip>
using namespace std;
float area1, area2, area3, area4;
int R1;
int trib;
int trih;
int top;
int bott;
int traph;
int majxis;
int minxis;
const float PI= 3.14159;
void handle_circle();
void handle_ellipse();
void handle_triangle();
void handle_trapizoid();
int main()
{
int number;
cout<< "I'm starting my program ";
cout<<"\n1.Circle";
cout<<"\n2.triangle";
cout<<"\n3.trapezoid";
cout<<"\n4.ellipse ";
cout<<"\nEnter the corresponding number of your choice(1-4):";
cin>> number;
if(number <= 0)
{
cout<<"Integer is invalid, try again ";
cin>> number;
}
if(number == 4)
{
handle_ellipse();
}
if(number == 3)
{
handle_trapizoid();
}
if(number == 2)
{
handle_triangle();
}
if(number == 1)
{
handle_circle();
}
}
void handle_trapizoid()
{
cout<<"\nWhat is the length of the top of the trapezoid? ";
cin>> top;
if(top <=0 )
{
cout<<"\n Invalid value for top length of trapezoid, try again";
}
else
{
cout<<"\nWhat is the length of the bottom of the trapezoid? ";
cin>> bott;
}
if (bott <= 0)
{
cout<<"Invalid value for bottom length of trapezoid, try again: ";
}
else
{
cout<<"What is the height of the trapezoid? ";
cin>>traph;
area3 = (top+bott)*0.5+traph;
}
if (traph <= 0)
{
cout<<"Invalid value for height of trapezoid";
}
else
{
cout<<"The area of a trapezoid with a bottom of " << bott << "and a top of " << top << "is " << area3;
}
}
void handle_ellipse()
{
cout<<"\nWhat is the length of the semi-major axis of the ellipse? ";
cin>> majxis;
if(majxis <=0)
{
cout<<"Invalid value for the semi-major axis, try again: ";
}
else
{
cout<<"What is the length for the semi-minor axis of the ellipse? ";
cin>> minxis;
area4= PI*minxis*majxis;
}
if(minxis <=0)
{
cout<<"Invalid value for the semi-minor axis, try again: ";
}
else
{
cout<<"The area of an ellipse with a semi-major axis of " << majxis<< "and a semi-minor axis of " << minxis << "is " << area4;
}
}
void handle_triangle()
{
cout<<"\nWhat is the length of the base of the triangle?";
cin>> trib;
if(trib<=0)
{
cout<<"\nInvalid Base of triangle, try again:";
}
else
{
cout<<"\nWhat is the height of the triangle? ";
cin>> trih;
area2 = (0.5*trib)*trih;
}
if(trih<=0)
{
cout<<"\nInvalid height of triangle, try again:";
}
else
{
cout<<"\nThe area of a trangle with a base of " << trib << "and a height of "<< trih <<" is " << area2;
}
}
void handle_circle()
{
cout<<"\nWhat is the radius of the circle?";
cin>> R1;
area1 = PI*(R1 *R1);
if( R1 <=0)
{cout<<"\nRadius must be greater than 0, try again";
cin>> R1;
}
else
{
cout<< "\nThe area of a circle with a radius of " << R1 << " is" << area1;
}
}
Also you can use switch statement as it is more faster than if statements
#include <iostream>
#include <iomanip>
using namespace std;
float area1, area2, area3, area4;
int R1;
int trib;
int trih;
int top;
int bott;
int traph;
int majxis;
int minxis;
const float PI= 3.14159;
void handle_circle();
void handle_ellipse();
void handle_triangle();
void handle_trapizoid();
int main()
{
int number;
cout<< "I'm starting my program ";
cout<<"\n1.Circle";
cout<<"\n2.triangle";
cout<<"\n3.trapezoid";
cout<<"\n4.ellipse ";
cout<<"\nEnter the corresponding number of your choice(1-4):";
cin>> number;
switch(number)
{
case 1:
handle_circle();
break;
case 2:
handle_triangle();
break;
case 3:
handle_ellipse();
break;
case 4:
handle_trapizoid();
break;
default:
{
cout<<"Integer is invalid, try again ";
}
}
}
void handle_trapizoid()
{
cout<<"\nWhat is the length of the top of the trapezoid? ";
cin>> top;
if(top <=0 )
{
cout<<"\n Invalid value for top length of trapezoid, try again";
}
else
{
cout<<"\nWhat is the length of the bottom of the trapezoid? ";
cin>> bott;
}
if (bott <= 0)
{
cout<<"Invalid value for bottom length of trapezoid, try again: ";
}
else
{
cout<<"What is the height of the trapezoid? ";
cin>>traph;
area3 = (top+bott)*0.5+traph;
}
if (traph <= 0)
{
cout<<"Invalid value for height of trapezoid";
}
else
{
cout<<"The area of a trapezoid with a bottom of " << bott << "and a top of " << top << "is " << area3;
}
}
void handle_ellipse()
{
cout<<"\nWhat is the length of the semi-major axis of the ellipse? ";
cin>> majxis;
if(majxis <=0)
{
cout<<"Invalid value for the semi-major axis, try again: ";
}
else
{
cout<<"What is the length for the semi-minor axis of the ellipse? ";
cin>> minxis;
area4= PI*minxis*majxis;
}
if(minxis <=0)
{
cout<<"Invalid value for the semi-minor axis, try again: ";
}
else
{
cout<<"The area of an ellipse with a semi-major axis of " << majxis<< "and a semi-minor axis of " << minxis << "is " << area4;
}
}
void handle_triangle()
{
cout<<"\nWhat is the length of the base of the triangle?";
cin>> trib;
if(trib<=0)
{
cout<<"\nInvalid Base of triangle, try again:";
}
else
{
cout<<"\nWhat is the height of the triangle? ";
cin>> trih;
area2 = (0.5*trib)*trih;
}
if(trih<=0)
{
cout<<"\nInvalid height of triangle, try again:";
}
else
{
cout<<"\nThe area of a trangle with a base of " << trib << "and a height of "<< trih <<" is " << area2;
}
}
void handle_circle()
{
cout<<"\nWhat is the radius of the circle?";
cin>> R1;
area1 = PI*(R1 *R1);
if( R1 <=0)
{cout<<"\nRadius must be greater than 0, try again";
cin>> R1;
}
else
{
cout<< "\nThe area of a circle with a radius of " << R1 << " is" << area1;
}
}