指數(shù)運(yùn)算
NSLog(@"%.f", pow(3,2) ); //result 9
NSLog(@"%.f", pow(3,3) ); //result 27
開平方運(yùn)算（計(jì)算兩點(diǎn)間的距離時(shí)用到）
NSLog(@"%.f", sqrt(16) ); //result 4
NSLog(@"%.f", sqrt(81) ); //result 9
上舍入
NSLog(@"res: %.f", ceil(3.000000000001)); //result 4
NSLog(@"res: %.f", ceil(3.00)); //result 3
下舍入
NSLog(@"res: %.f", floor(3.000000000001)); //result 3
NSLog(@"res: %.f", floor(3.9999999)); //result 3
四舍五入
NSLog(@"res: %.f", round(3.5)); //result 4
NSLog(@"res: %.f", round(3.46)); //result 3
NSLog(@"res: %.f", round(-3.5)); //NB: this one returns -4
最小值
NSLog(@"res: %.f", fmin(5,10)); //result 5
最大值
NSLog(@"res: %.f", fmax(5,10)); //result 10
絕對(duì)值
NSLog(@"res: %.f", fabs(10)); //result 10
NSLog(@"res: %.f", fabs(-10)); //result 10
