比如
{ 3x -5 ,1<= x <2
y = { 2cosx + 1 , 2<= x <4
{ sqrt(1+x^2) , 4<= x <6
{ x^2 -4x +5 , 其他
#include<iostream>
#include<math.h>
void main(){
double x , y;
cout <<"x = ";
cin >> x;
switch(int(x)){
case 1:y =3 * x -5;break;
case 2:
case 3:y = 2 * cos(x) +1 ;break;
case 4:
csse 5:y = sqrt(1+x*X); brea;
default: y = x*X - 4*x + 5;
}
cout <<"y ="<<y<<endl;
}
