C++数学常用函数及功能

王浩宇

[size=16.002px]以下是C++中常用的数学函数及其功能的表格，附带简单的案例说明：

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C++ 数学函数（需包含 <cmath> 头文件）

函数名

功能描述

示例代码

sqrt(x)

计算 x 的平方根double x = sqrt(16); // x = 4.0

pow(x, y)

计算 x 的 y 次方double x = pow(2, 3); // x = 8.0

abs(x)

计算 x 的绝对值（适用于整数）int x = abs(-10); // x = 10

fabs(x)

计算 x 的绝对值（适用于浮点数）double x = fabs(-10.5); // x = 10.5

exp(x)

计算 e 的 x 次方double x = exp(1); // x ≈ 2.71828

log(x)

计算 x 的自然对数（以 e 为底）double x = log(2.71828); // x ≈ 1.0

log10(x)

计算 x 的以 10 为底的对数double x = log10(100); // x = 2.0

sin(x)

计算 x 的正弦值（x 为弧度）double x = sin(3.14159 / 2); // x ≈ 1.0

cos(x)

计算 x 的余弦值（x 为弧度）double x = cos(0); // x = 1.0

tan(x)

计算 x 的正切值（x 为弧度）double x = tan(3.14159 / 4); // x ≈ 1.0

asin(x)

计算 x 的反正弦值（返回值范围为 [-π/2, π/2]）double x = asin(1); // x ≈ 1.5708 (π/2)

acos(x)

计算 x 的反余弦值（返回值范围为 [0, π]）double x = acos(0); // x ≈ 1.5708 (π/2)

atan(x)

计算 x 的反正切值（返回值范围为 [-π/2, π/2]）double x = atan(1); // x ≈ 0.7854 (π/4)

atan2(y, x)

计算 y/x 的反正切值（返回值范围为 [-π, π]）double x = atan2(1, 1); // x ≈ 0.7854 (π/4)

ceil(x)

向上取整，返回不小于 x 的最小整数double x = ceil(3.2); // x = 4.0

floor(x)

向下取整，返回不大于 x 的最大整数double x = floor(3.9); // x = 3.0

round(x)

四舍五入，返回最接近 x 的整数double x = round(3.5); // x = 4.0

fmod(x, y)

计算 x 除以 y 的浮点余数double x = fmod(10.5, 3); // x = 1.5

hypot(x, y)

计算直角三角形的斜边长度（sqrt(x² + y²)）double x = hypot(3, 4); // x = 5.0

max(x, y)

返回 x 和 y 中的较大值int x = max(3, 5); // x = 5

min(x, y)

返回 x 和 y 中的较小值int x = min(3, 5); // x = 3

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示例代码：cpp
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#include <iostream>#include <cmath> // 包含数学函数using namespace std;int main() {    // 平方根    cout << "sqrt(16) = " << sqrt(16) << endl;    // 幂次方    cout << "pow(2, 3) = " << pow(2, 3) << endl;    // 绝对值    cout << "abs(-10) = " << abs(-10) << endl;    cout << "fabs(-10.5) = " << fabs(-10.5) << endl;    // 指数和对数    cout << "exp(1) = " << exp(1) << endl;    cout << "log(2.71828) = " << log(2.71828) << endl;    cout << "log10(100) = " << log10(100) << endl;    // 三角函数    cout << "sin(π/2) = " << sin(3.14159 / 2) << endl;    cout << "cos(0) = " << cos(0) << endl;    cout << "tan(π/4) = " << tan(3.14159 / 4) << endl;    // 反三角函数    cout << "asin(1) = " << asin(1) << endl;    cout << "acos(0) = " << acos(0) << endl;    cout << "atan(1) = " << atan(1) << endl;    // 取整函数    cout << "ceil(3.2) = " << ceil(3.2) << endl;    cout << "floor(3.9) = " << floor(3.9) << endl;    cout << "round(3.5) = " << round(3.5) << endl;    // 浮点余数    cout << "fmod(10.5, 3) = " << fmod(10.5, 3) << endl;    // 斜边长度    cout << "hypot(3, 4) = " << hypot(3, 4) << endl;    // 最大值和最小值    cout << "max(3, 5) = " << max(3, 5) << endl;    cout << "min(3, 5) = " << min(3, 5) << endl;    return 0;}

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输出结果：
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sqrt(16) = 4pow(2, 3) = 8abs(-10) = 10fabs(-10.5) = 10.5exp(1) = 2.71828log(2.71828) = 1log10(100) = 2sin(π/2) = 1cos(0) = 1tan(π/4) = 1asin(1) = 1.5708acos(0) = 1.5708atan(1) = 0.785398ceil(3.2) = 4floor(3.9) = 3round(3.5) = 4fmod(10.5, 3) = 1.5hypot(3, 4) = 5max(3, 5) = 5min(3, 5) = 3

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[size=16.002px]这些函数是C++中常用的数学计算工具，涵盖了基本的算术运算、三角函数、对数函数、取整函数等。