The original [problem description]
Known to use the following formula to calculate PI approximation, given a PI approximation e, a programming using the following formula for the closest e and less than the approximate value of e PI, as well as the number of iterations n (greater than or equal to 1),
Two-thirds of PI/2=2/1 (x) (four thirds 4/5) x x x x x 6/7 (6/5)... X (2 n/(2 n - 1) x2n/(2 n + 1)]
[form] input
From the console input e (e is greater than 2.6666667, less than 3.1415926) the value of the
[] output form
Output is the closest to and less than the approximate value of e e PI, as well as the number of iterations n (with a space space, and the output of PI when seven valid decimal Numbers),
[sample input]
3.12
[sample output]
3.1195472 35
[example]
Input of PI approximation e 3.12, when the n is 35 calculated PI value of 3.1195472, less than the value of the given precision, when n is 36, calculation of PI value of 3.1201491, is greater than the value of the given precision, so the closest e and using the above formula obtained is less than e PI approximation is 3.1195472, corresponding to the number of iterations of 35,
Note:
In order to ensure the calculation precision, please use the double data type calculation data save,

#include
Int main ()
{

double x;
float y;
Float f (double x);
Printf (" please input Π: ");
The scanf (" % f ", & amp; X);
Printf (" % 7 lf ", 2 * y);
;


}
Float f (double) a
{
Float k;

for(int i=1; 2 * k<=a; I++)
{
Float m;
I/m=2 * (2 * I - 1) * 2 * I/(2 * I + 1);
K=k * m;

}
The return of k;


}

CodePudding user response:

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CodePudding user response:

Child function f, k without an initial value, so for the first time will determine failure, jump out

CodePudding user response:

Also, although I don't know why you use double x, but since using the double, the input, please use the scanf (" % lf ", & amp; x)

CodePudding user response:

I - I/(2 * 2 * 1) * 2 * I/(2 * I + 1) there is always an integer arithmetic
It is good to change the first 2 to 2.0
Otherwise this is integer arithmetic, although m is a floating point number, the result of the class integer arithmetic is always 0 have a fart to use

CodePudding user response:

I hope it can help you: https://blog.csdn.net/it_xiangqiang/category_10581430.html
I hope it can help you: https://blog.csdn.net/it_xiangqiang/category_10768339.html