数组实现多项式的加减乘运算

"fatal.h"//头文件

1 #include<stdio.h>
2 #include<stdlib.h>
3 #define Error(Str) FatalError(Str)
4 #define FatalError(Str) fprintf(stderr,"%s\n",Str),exit(1);

  1 /* This code doesn‘t really do much */
  2 /* Thus I haven‘t bothered testing it */
  3 
  4 #include "fatal.h"//头文件
  5 
  6 #define MaxDegree 100//定义多项式最大指数是100
  7 
  8 static int
  9 Max( int A, int B )
 10 {
 11     return A > B ? A : B;//返回AB中的最大值
 12 }
 13      //定义一个结构体数组
 15         typedef struct
 16         {
 17             int CoeffArray[ MaxDegree + 1 ];//需要多存储一个常数项
 18             int HighPower;//存储多项式的最高项的指数
 19         } *Polynomial;
 20 /* END */
 21 
 22 /* START: fig3_19.txt */
 23         void
 24         ZeroPolynomial( Polynomial Poly )//初始化多项式
 25         {
 26             int i;
 27 
 28             for( i = 0; i <= MaxDegree; i++ )
 29                 Poly->CoeffArray[ i ] = 0;
 30             Poly->HighPower = 0;
 31         }
 32 /* END */
 33 
 34 /* START: fig3_20.txt */
 35         void                          //两个多项式相加
 36         AddPolynomial( const Polynomial Poly1, const Polynomial Poly2,
 37                        Polynomial PolySum )
 38         {
 39             int i;
 40 
 41             ZeroPolynomial( PolySum );
 42             PolySum->HighPower = Max( Poly1->HighPower,
 43                                       Poly2->HighPower );
 44 
 45             for( i = PolySum->HighPower; i >= 0; i-- )
 46                 PolySum->CoeffArray[ i ] = Poly1->CoeffArray[ i ]
 47                                                + Poly2->CoeffArray[ i ];
 48         }
 49 /* END */
 50 
 51 /* START: fig3_21.txt */
 52         void                                    //两个多项式相乘
 53         MultPolynomial( const Polynomial Poly1,
 54                         const Polynomial Poly2, Polynomial PolyProd )
 55         {
 56             int i, j;
 57 
 58             ZeroPolynomial( PolyProd );
 59             PolyProd->HighPower = Poly1->HighPower + Poly2->HighPower;
 60 
 61             if( PolyProd->HighPower > MaxDegree )
 62                 Error( "Exceeded array size" );
 63             else
 64                 for( i = 0; i <= Poly1->HighPower; i++ )
 65                     for( j = 0; j <= Poly2->HighPower; j++ )
 66                         PolyProd->CoeffArray[ i + j ] +=
 67                                 Poly1->CoeffArray[ i ] *
 68                                 Poly2->CoeffArray[ j ];
 69         }
 70 /* END */