c math.h常用函数

#define _USE_MATH_DEFINES
#include <math.h>

int (){

//  double pow(double x, double y)          返回 x 的 y 次幂。

//  double fabs(double x)                   返回 x(浮点类型) 的绝对值。
//  int abs(int x);                         返回 x(整型) 的绝对值。
    double x = exp(2);
    double y = pow(10,2);
    double z = log(exp(1));
    printf("exp(2) is %f n",x);
    printf("M_PI is %f n", M_PI);
    printf("pow(10,2) is %f n",y);
    printf("log(exp(1)) is %f n",z);
    printf("log10(1000) is %f n",log10(1000));
    printf("cos(M_Pi) is %f n",cos(M_PI));
    printf("fabs(-10.05) is %f n",fabs(-10.05));
    printf("abs(-10) is %d n",abs(-10));
}


/* output:
exp(2) is 7.389056
M_PI is 3.141593
pow(10,2) is 100.000000
log(exp(1)) is 1.000000
log10(1000) is 3.000000
cos(M_Pi) is -1.000000
fabs(-10.05) is 10.050000
abs(-10) is 10
*/