C ++简介：生成转换表，以使用while或do / while循环将度转换为弧度

Question

My problem states: Write a program using a while or do/while loop to generate a conversion table for converting degrees to radians. The degree values start at 0 degrees, increment by 10 and go through 360 degrees.

I'm very, very new at coding in general, and this is for my C++ class

I've come up with this so far:

#include <iostream>

using namespace std;

int main()
{
    double degrees, radians, degree1    

    do  
        {
            radians = 3.14159265/180
            degree1 = (0 * radians)
            degrees = (degree1 + 10) * radians;
        }
    while (degrees > 360);

    return 0;
}

However, I don't have a great grasp on do-while loops, and I'm having troubles getting the code to run. Any tips would be greatly appreciated!

Answer 1

You'll probably want to have an array to store the conversions. For example: degrees_to_radians[180] = 3.14

In the do while loop, have the array index be the current value in degrees, and set it equal to that value of degrees converted to radians.

Answer 2

The do-while guarantees that at least 1 loop is going to be done, and it is going to loop until the while condition is satified. Then you have to change it to <=360 for your purpose. The following code does what you want:

#include <iostream>
using namespace std;

double deg2rad(double deg)
{
     return deg*3.14159265/180.f;
}

int main()
{
    double degrees = 0;
    do  
    {  
        cout << degrees << "\t" << deg2rad(degrees) << std::endl;
        degrees += 10;
    }
    while (degrees <= 360);
    return 0;
}

Suggestion: try to use boost constants. Either C/C++ constants or Boost constants: How to use the PI constant in C++

Answer 3

The structure of a Do-While loop is "do stuff while something is true". Start with something simple. Since this is a class assignment, I don't want to just give you the answer, but I'll give a similar example.

Say you want to count to 100 by fives. You want to start at 0, stop at 100, and increment by 5. So you would want a Do-While that looks like this:

int count = 0;
do {
    count = count + 5;        // increment by 5
    cout << count << endl;    // print out the value of count
} while (count <= 100);

Remember, the loop continues while the statement is true. So in this case, you will keep doing the "stuff" while count is less-than or equal-to 100. The sample code you provided only runs through the loop once because the condition degrees > 360 is false after it does the calculations inside the loop (after which degrees is 31.415...).

I'm guessing you just learned For-Loops and are now supposed to do something you'd normally use a For-Loop to do using a While/Do-While instead. If you were to do the same example as a For-Loop, it'd look like this:

for (int count = 0; count <= 100; count += 5) {
    cout << count << endl;    // print out the value of count
}

Now, instead of printing out the value, do your radians/degrees conversions and store them in an array as @Tyler said.

Also, be mindful of your semicolons.