发布于 2011-10-11 00:39:53
由于int
s不能存储浮点数,浮点数的十进制部分将被截断,您将得到整数:
float x = 3.14159;
int y = (int)x;
这是因为int
只能存储整数,所以它只存储x
的整数部分。
另见gnu C Library Rounding Functions
— Function: double ceil (double x)
— Function: float ceilf (float x)
— Function: long double ceill (long double x)
— Function: double floor (double x)
— Function: float floorf (float x)
— Function: long double floorl (long double x)
— Function: double trunc (double x)
— Function: float truncf (float x)
— Function: long double truncl (long double x)
— Function: double rint (double x)
— Function: float rintf (float x)
— Function: long double rintl (long double x)
— Function: double nearbyint (double x)
— Function: float nearbyintf (float x)
— Function: long double nearbyintl (long double x)
— Function: double round (double x)
— Function: float roundf (float x)
— Function: long double roundl (long double x)
— Function: long int lrint (double x)
— Function: long int lrintf (float x)
— Function: long int lrintl (long double x)
— Function: long long int llrint (double x)
— Function: long long int llrintf (float x)
— Function: long long int llrintl (long double x)
— Function: long int lround (double x)
— Function: long int lroundf (float x)
— Function: long int lroundl (long double x)
— Function: long long int llround (double x)
— Function: long long int llroundf (float x)
— Function: long long int llroundl (long double x)
— Function: double modf (double value, double *integer-part)
— Function: float modff (float value, float *integer-part)
— Function: long double modfl (long double value, long double *integer-part)
发布于 2011-10-11 00:51:30
但是3.999也等于3,如果你只是把它转换成int。
float value = 3.14159f;
int intValue = (int)value;
float fractional = fmodf(value, (float)intValue);
if(fractional > .5f)
intValue++;
intValue是你的四舍五入。
https://stackoverflow.com/questions/7720238
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