DS1-3

#include <stdio.h>
#include <string.h>
 
#define MAXSIZE 1024
 
double polynomial[MAXSIZE];
 
double SumPolynomial(int ini, double polynomial[], double x);
 
int main()
{
    memset(polynomial, 0, sizeof(polynomial));
    printf("Please input your polynomial:\n");
    double coefficient;
    int exponential;
    double x;
    int max=0;
    int cnt=0;
    while(1)
    {
        //printf("test!\n");
        scanf("%lf %d", &coefficient, &exponential);
        //++cnt;
        if((exponential!=0)||(coefficient!=0.0))//The "&&" is wrong,while the "||" is right.
        {
            polynomial[exponential]=coefficient;
            if(exponential>max)
                max=exponential;
            //printf("%d: %lf %d\n", cnt, coefficient, exponential);
        }
        else
            break;
    }
    printf("Please input the values of x:\n");
    scanf("%lf", &x);
    //printf("The value of max is equal to %d.\n", max);
    /*for(i=max; i>=0; --i)
    {
        printf("|%d:%f|", i, polynomial[i]);
        if(i!=0)
            printf(",");
        else
            printf(".");
    }*/
    //printf("\n");
    double sum;
    sum=SumPolynomial(max, polynomial, x);
    printf("f(%f)=", x);
    int i;
    for(i=max; i>=0; --i)
    {
        if(polynomial[i]!=0)
        {
            if(i!=max)
                printf("+");
            printf("%f*%f^%d", polynomial[i], x, i);
        }
    }
    printf("=%f.\n",sum);
    return 0;
}
 
double SumPolynomial(int ini, double polynomial[], double x)
{
    double sum=polynomial[ini];
    int i;
    for(i=ini-1; i>=0; --i)
    {
        //printf("exponential=%d:sum=%f,polynomial[%d]=%f\n", i, sum);
        sum=sum*x+polynomial[i];// "i" is right, "ini" is wrong!
        //printf("exponential=%d:sum=%f\n", i, sum);
    }
        //???:check "sum".
    return sum;
}