Thread: Any help would be appreciated.....

I'm having difficulties with this assignment. I thought I was doing it correctly but unfortuneatley I'm receiving parse errors. I'm writing this program in SSH Secure Shell.

Here is my current code;

Code:

#include <stdio.h> 
#include <math.h> 
#define pi 3.141592 
main() 
{ 
       int degree, q, a, b, c, d; 
       double x, y, y2, z; 
       printf("Enter angle in degrees:\n") ; 
       scanf("%d", &degree) ; 
       x = ((pi*degree)/180) ; 
       y=cos(x); 

       printf("True value of cos(x) is %d\n",y); 

       char ch; 
       do 
       { 
       printf("Enter a character; 0 to exit\n"); 
       ch = getchar(); 
       getchar(); 
       switch(ch) 
         { 
            case 'a': 
               y2=(y-((x*x*x*x*x*x)/(6*5*4*3*2*1))); 
            case 'b': 
               y2=(y+((x*x*x*x)/(4*3*2*1))); 
            case 'c': 
               y2=(y-((x*x)/(2*1))); 
            case 'd': 
               y2=(y); 
          } 
if (ch = a) printf("4 term approximation\nApproximate cos(x) = %f\nRelative erro 
r = 20 percent", y2); 
       } 
       while (ch != 'q'); 
       exit(z); 
}

It seems as though my looping is not working correctly....

My Parse Errors;

Code:

Enter angle in degrees: 
45 
True value of cos(x) is -1073081832 
Enter a character; 0 to exit 
0 
Enter a character; 0 to exit 
0 
Enter a character; 0 to exit 
0 
Enter a character; 0 to exit 
0 
Enter a character; 0 to exit 
4 
Enter a character; 0 to exit 
3 
Enter a character; 0 to exit 
2 
Enter a character; 0 to exit 
1 
Enter a character; 0 to exit 

Stopped

And last but not least this is my assignment....

Code:

   Scan the angle in degrees x_deg (=45). Express this angle in 
   radians by using x=PI*x_deg/180, and calculate Y=cos(x) by 
   using the math.h library of functions. 

   Your objective in this quiz is to compare the so caclulated 
   value of Y=cos(x) with the approximate value y obtained by 
   using 1, 2, 3, and 4 leading terms of the Taylor series: 

       cos(x) = 1 - x^2/2! + x^4/4! - x^6/6! + ... 

   Recall that k!=k*(k-1)*(k-2)* ... *3*2*1 . 

   Use a do/while loop in conjunction with a switch statement 
   switch(ch). Enter the character '1' for one term approximation 
   '2' for two terms, etc., by using getchar() function. Use 
   '0' to exit the program. 

   Let your opening case calculate the fourth term x^6/6!, let the 
   subsequent case calculate the x^4/4! term, etc. (In this way, 
   you wan't need to use a break statement within your switch). 

   Evaluate the corresponding Y , print the result in one line, 
   and the relative error (Y-y)/Y in another line. 

   Execute your program for all four cases (with corresponding 
   printouts). 

                               Note: 

   To avoid printing on the screen: 

      Enter a character; 0 to Exit 

   twice in a row, insert the line 

      getchar(); 

   after each of the lines 

    scanf("%lf",&x_deg); 

    and 

    n_term=getchar(); 

    in your program. 


............................................ 

Your output should look like this: 

True value of cos(x) = 0.707107 
Enter a character; 0 to Exit 
1 
1 term approximation 
Approximate cos(x) = 1.000000 
Relative error = -41.421356 percent 
Enter a character; 0 to Exit 
2 
2 terms approximation 
Approximate cos(x) = 0.691575 
Relative error = 2.196545 percent 
Enter a character; 0 to Exit 
3 
3 terms approximation 
Approximate cos(x) = 0.707429 
Relative error = -0.045598 percent 
Enter a character; 0 to Exit 
4 
4 terms approximation 
Approximate cos(x) = 0.707103 
Relative error = 0.000504 percent 
Enter a character; 0 to Exit 
0 

*/

Thanks for any feedback,
-Steve

ok i tried changing the ch = a to ch == a and it still isnt working, so i changed the a to 4 the b to 3 the c to 2 and the d to 1 and left it as ch = 4 and that sort of worked, also i dont understand about the declaring a variable in the middle. heres my new code and the errors im getting:

Code:

#include <stdio.h>
#include <math.h>
#define pi 3.141592
main()
{
        int degree, q, a, b, c, d;
        double x, y, Y, z, error;
        printf("Enter angle in degrees:\n") ;
        scanf("%d", &degree) ;
        x = ((pi*degree)/180) ;
        Y=cos(x);

        printf("True value of cos(x) is %d\n",Y);

        error = ((Y-y)/Y);

        char ch;
        do
        {
        printf("Enter a character; 0 to exit\n");
        ch = getchar();
        getchar();
        switch(ch)
          {
             case '4':
                y=(y-((x*x*x*x*x*x)/(6*5*4*3*2*1)));
             case '3':
                y=(y+((x*x*x*x)/(4*3*2*1)));
             case '2':
                y=(y-((x*x)/(2*1)));
             case '1':
                y=(y);
           }
if (ch = '4') printf("4 term approximation\nApproximate cos(x) = %f\nRelative er
ror = %f percent\n", y, error);
if (ch = '3') printf("3 term approximation\nApproximate cos(x) = %f\nRelative er
ror = %f percent\n", y, error);
if (ch = '2') printf("2 term approximation\nApproximate cos(x) = %f\nRelative er
ror = %f percent\n", y, error);
if (ch = '1') printf("1 term approximation\nApproximate cos(x) = %f\nRelative er
ror = %f percent\n", y, error);
        }
        while (ch != '0');

exit(0);
}

Code:

Enter angle in degrees:
45
True value of cos(x) is -1073081832
Enter a character; 0 to exit
3
4 term approximation
Approximate cos(x) = 0.000000
Relative error = 1.000000 percent
3 term approximation
Approximate cos(x) = 0.000000
Relative error = 1.000000 percent
2 term approximation
Approximate cos(x) = 0.000000
Relative error = 1.000000 percent
1 term approximation
Approximate cos(x) = 0.000000
Relative error = 1.000000 percent
Enter a character; 0 to exit
0
4 term approximation
Approximate cos(x) = 0.000000
Relative error = 1.000000 percent
3 term approximation
Approximate cos(x) = 0.000000
Relative error = 1.000000 percent
2 term approximation
Approximate cos(x) = 0.000000
Relative error = 1.000000 percent
1 term approximation
Approximate cos(x) = 0.000000
Relative error = 1.000000 percent
Enter a character; 0 to exit

the answer for what cos equals is wrong and the loop repeats with out exit and gives the same result no matter what ch i put in,
thanks for any feedback