對數(頭文件c.math)
//C++11起
//返回arg的自然對數(底數爲e)
double log (double arg);
float log (float arg);
long double log (long double arg);
//C++11起
//返回arg的底數爲10的對數
float log10 ( float arg );
float log10f( float arg );
double log10 ( double arg );
long double log10 ( long double arg );
long double log10l( long double arg );
//C++11起
//返回arg的底數爲2的對數
float log2 ( float arg );
float log2f( float arg );
double log2 ( double arg );
long double log2 ( long double arg );
long double log2l( long double arg );
//求n的底數爲m的對數
double res = log(n)/log(m);
向上取整(頭文件c.math)
//C++11起
//返回不小於arg的最小整數(返回值小數點後均爲0)
float ceil ( float arg );
float ceilf( float arg );
double ceil ( double arg );
long double ceil ( long double arg );
long double ceill( float arg );
向下取整(頭文件c.math)
//C++11起
//返回不大於arg的最大整數(返回值小數點後均爲0)
float floor ( float arg );
float floorf( float arg );
double floor ( double arg );
long double floor ( long double arg );
long double floorl( long double arg );