用c++类求分段函数

#include<iostream>

#include<math.h>

#include <iomanip>

using namespace std;

class text{

private:

double xx;

public:

text(double x){

xx=x;

}

double sec(){

double fx;

if(xx<0){

fx=fabs(xx);

}

else if(0<=xx&&xx<2){

fx=sqrt(xx+1);

}

else if(2<=xx&&xx<4){

fx=pow(xx+2,5);

}

else{

fx=2*xx+5; 

}

return fx;

}

};

int main(){

double a;

cin>>a;

text b(a);

printf("%.2f",b.sec());

}