如何在C中获得更高的精度？ [英] How to get more precision in C ?
问题描述
我想在我的数值计算程序中获得至少8位数的精度。我尝试过使用双打，但我一直得到
结果只有小数点后6位。例如。
#include< stdio.h>
#define M_PI 3.14159265358979323846 / * M_PI未在math.h中定义
根据我的编译器* /
int main（无效）
{
双倍;
s = M_PI;
printf（"％f"，s）;
返回0;
}
I would like to have precision upto atleast 8 digits in my numerical
computation program. I have tried using doubles but I keep getting
results only till 6 places after decimal. eg.
#include <stdio.h>
#define M_PI 3.14159265358979323846 /* M_PI is not defined in math.h
according to my compiler*/
int main(void)
{
double s;
s = M_PI;
printf("%f", s);
return 0;
}
推荐答案
>我希望在我的数字
>I would like to have precision upto atleast 8 digits in my numerical
$ b $中有至少8位数的精度b>计算程序。我尝试过使用双打但是我一直只得到结果直到小数点后6位。例如。
>computation program. I have tried using doubles but I keep getting
results only till 6 places after decimal. eg.
您只能在小数点后打印* 6位数。在实际计算中你可能会获得更高的精确度。
尝试：printf（"％300.200f"，s）;
虽然这主要用于调试。双赢不要
几乎有这么多数字的精确度。
You only *print* 6 digits after the decimal. You may be getting greater
precision in the actual computation.
Try: printf("%300.200f", s);
although this is primarily useful for debugging. A double won''t
have nearly this many digits of precision.
> #include< stdio.h>
#define M_PI 3.14159265358979323846 / * M_PI未在math.h中定义
根据我的编译器* /
int main（void）
{
double s ;
s = M_PI;
printf（"％f"，s）;
返回0;
}
>#include <stdio.h>
#define M_PI 3.14159265358979323846 /* M_PI is not defined in math.h
according to my compiler*/
int main(void)
{
double s;
s = M_PI;
printf("%f", s);
return 0;
}
在文章< bd ************************* ********* @ q27g2000prf。 googlegroups.com>，
pereges< Br ***** @ gmail.comwrote：
In article <bd**********************************@q27g2000prf. googlegroups.com>,
pereges <Br*****@gmail.comwrote:
>我想要在我的数值计算程序中，精度达到至少8位数。我尝试过使用双打但是我一直只得到结果直到小数点后6位。例如。
>I would like to have precision upto atleast 8 digits in my numerical
computation program. I have tried using doubles but I keep getting
results only till 6 places after decimal. eg.
> #include< stdio.h>
#define M_PI 3.14159265358979323846 / * M_PI未在math.h中定义/>根据我的编译器* /
>#include <stdio.h>
#define M_PI 3.14159265358979323846 /* M_PI is not defined in math.h
according to my compiler*/
> int main（void）
{
double s;
s = M_PI;
printf（"％f"，s）;
返回0;
}
>int main(void)
{
double s;
s = M_PI;
printf("%f", s);
return 0;
}
使用％f格式指定精度，例如％.60f。 ％f的默认值
为6.
另外，为了安全起见，请确保输出以换行符结尾。例如，
printf（"％。9f \ n"，s）;
-
问：为什么鸡穿过莫比乌斯带？
答：有多种原因。
Specify a precision with your %f format, such as %.60f . The default
for %f is 6.
Also, to be safe, ensure your output ends in a newline. For example,
printf("%.9f\n", s);
--
Q: Why did the chicken cross the Mobius strip?
A: There were manifold reasons.
4月10日，8：53 * pm，pereges< Brol ... @ gmail.comwrote：
On Apr 10, 8:53*pm, pereges <Brol...@gmail.comwrote:
我希望精确到达我的数字中的至少8位数/>
计算程序。我尝试过使用双打，但我一直得到
结果只有小数点后6位。例如。
#include< stdio.h>
#define M_PI 3.14159265358979323846 / * M_PI未在math.h中定义
根据我的编译器* /
int main（无效）
{
* * * * double s;
* * * * s = M_PI;
* * * * printf（"％f"，s）;
返回0;
}
I would like to have precision upto atleast 8 digits in my numerical
computation program. I have tried using doubles but I keep getting
results only till 6 places after decimal. eg.
#include <stdio.h>
#define M_PI 3.14159265358979323846 /* M_PI is not defined in math.h
according to my compiler*/
int main(void)
{
* * * * double s;
* * * * s = M_PI;
* * * * printf("%f", s);
return 0;
}
试试这样：
＃包括< stdio.h>
#include< float.h>
static const double pi_approximation =
3.1415926535897932384626433832795;
int main（无效）{
printf（我的近似值为％。* g\ n，DBL_DIG + 1，
pi_approximation）;
返回0;
}
Try it this way:
#include <stdio.h>
#include <float.h>
static const double pi_approximation =
3.1415926535897932384626433832795;
int main(void) {
printf("My pi approximation is %.*g\n", DBL_DIG + 1,
pi_approximation);
return 0;
}
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