如何在ios4的xcode for iOS中將浮點數四捨五入爲整數？

Question

可能重複：
Objective-c: How to round off Float values?

我知道它與NSNumberformatter類，任何示例代碼嗎？

Answer 1

由於int s不能存儲浮點數，浮點數的小數部分將被截斷，你將留下的整數：

float x = 3.14159; 
int y = (int)x; 

這工作，因爲int只能夠

：存儲整數，因此它只是存儲 x

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見的整數部分也gnu C Library Rounding Functions的

— 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) 

Answer 2

但是3.999也等於3，如果你只是將它轉換爲int。

float value = 3.14159f; 
int intValue = (int)value; 
float fractional = fmodf(value, (float)intValue); 
if(fractional > .5f) 
    intValue++; 

intValue是你的四捨五入整數。