使用结构的多项式求值[使用C ++程序]
要了解使用结构的多项式的实现，请参考使用结构的多项式加法。
多项式评估是指为多项式变量的特定值找到多项式表达式的结果。
示例
P(x)= 4x3+6x2+7x+9 where x=2 then,Result = 4(2)3+6(2)2+7(2)1+9 = 4(8)+6(4)+7(2)+9= 32+24+14+9= 79
使用多项式的每个项的结构存储多项式，因此程序使用结构数组。
Struct polynomial
{
int coefficient;
int exponent;
};算法
Eval (struct poly p[10],int n,int x)1.) [Initialize segment variables]
[Initialize Counter] Set i=0,sum=02.) Repeat step 3 while i<n 3.) sum=sum+p[i].coeff*pow(x,p[i].expo)4.) Return sum;5.) Exit使用结构进行多项式评估的C++程序
#include<iostream>
#include<math.h>
using namespace std;
/* declare structure for polynomial */
struct poly
{
int coeff;
int expo;
};
/* function prototypes */
int readPoly(struct poly []);
void displayPoly( struct poly [],int terms);
int eval(int n1,struct poly []);
int main(){
int n1;
int value;
struct poly p1[20];
cout<<"\n Enter the polynomial details:";
n1=readPoly(p1);
cout<<"\n The polynomial is: ";
displayPoly(p1,n1);
value=eval(n1,p1);
cout<<"\n The Resultant value of the polynomial is:"<<value<<endl;
return 0;
}
int readPoly(struct poly p[])
{
int t1,i;
cout<<"\n Enter the total number of terms in the polynomial: ";
cin>>t1;
cout<<"\n Enter the COEFFICIENT and EXPONENT "<<endl;
for(i=0;i<t1;i++)
{
cout<<" Enter the Coefficient("<<i+1<<"):";
cin>>p[i].coeff;
cout<<" Enter the Exponent("<<i+1<<"):";
cin>>p[i].expo;
}
return(t1);
}
void displayPoly(struct poly p[10],int term)
{
int k;
for(k=0;k<term-1;k++)
cout<<p[k].coeff<<"(x^"<<p[k].expo<<")+";
cout<<p[k].coeff<<"(x^"<<p[k].expo<<")";
}
int eval(int n1,struct poly p1[])
{
int i,sum,x;
cout<<"\n\n Enter the value of x for evaluation: ";
cin>>x;
sum=0;
for(i=0;i<n1;i++)
sum=sum + p1[i].coeff*pow(x,p1[i].expo);
return(sum);
}输出结果
Enter the polynomial details: Enter the total number of terms in the polynomial: 4 Enter the COEFFICIENT and EXPONENT Enter the Coefficient(1):4 Enter the Exponent(1):3 Enter the Coefficient(2):6 Enter the Exponent(2):2 Enter the Coefficient(3):7 Enter the Exponent(3):1 Enter the Coefficient(4):9 Enter the Exponent(4):0 The polynomial is: 4(x^3)+6(x^2)+7(x^1)+9(x^0) Enter the value of x for evaluation: 2 The Resultant value of the polynomial is:79