log10, log10f, log10l - C++ Builder 参考手册

函数原型	C90	C99	C++98	C++11
double log10(double x);	√	√	√	√
float log10f(float x);		√
long double log10l(long double x);		√
float log10(float x);			√	√
long double log10(long double x);			√	√

头文件：

#include <cmath>

命名空间：

std

参数：

x：浮点数，定义域范围为 [0, +Infinity]

返回值：

x 的常用对数值，x 的以 10 为底的对数值，值域范围为 [-Infinity, +Infinity]
NAN：定义域错误，此时全局变量 errno 的值为 EDOM。

例子：

void __fastcall TForm1::Button1Click(TObject *Sender)
{
Memo1->Lines->Add(L"log10( 0   ) = " + FloatToStr(std::log10( 0.0    )));
Memo1->Lines->Add(L"log10( 3e-69) = " + FloatToStr(std::log10( 3e-69   )));
Memo1->Lines->Add(L"log10( 0.01) = " + FloatToStr(std::log10( 0.01 )));
Memo1->Lines->Add(L"log10( 1   ) = " + FloatToStr(std::log10( 1.0    )));
Memo1->Lines->Add(L"log10( 12.34) = " + FloatToStr(std::log10(12.34 )));
Memo1->Lines->Add(L"log10(100   ) = " + FloatToStr(std::log10(100.0 )));
Memo1->Lines->Add(L"log10(5.6e98) = " + FloatToStr(std::log10(5.6e98   )));
Memo1->Lines->Add(L"log10( +∞   ) = " + FloatToStr(std::log10( Infinity)));
Memo1->Lines->Add(L"log10( -2   ) = " + FloatToStr(std::log10(-2.0    )));
Memo1->Lines->Add(L"log10( -∞   ) = " + FloatToStr(std::log10(-Infinity)));
}

兼容性：

函数 \ C++ Builder 编译器	bcc32	clang32	clang64
log10	√	√	√
log10f		版本 ≥ 10.2 Tokyo Update 1	√
log10l	√	√	√

相关链接：

• exp • exp2 • expm1 • log • log1p • log2 • pow • pow10 • sqrt • _matherr • 浮点数异常处理

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