用c语言建立一元稀疏多项式简单计算器：(1) 输入并建立多项式；(2) 输出多项式,输出形式为整数序列：n,c1,e1, c2,e2, cn,en,其中n是多项式的项数,ci,ei,分别是第i项的系数和指数,序列按指数降序排序；(3) 多项式a和b相加,建立多项式a+b

在C语言中，你可以使用结构体来表示多项式的每一项，数组来存储所有项，并实现输入、输出和相加的功能。以下是一个简单的示例：

#include <stdio.h>
#include <stdlib.h>

// 定义多项式项的数据结构
typedef struct {
    int coefficient; // 系数
    int exponent;     // 指数
} Term;

// 用于比较指数的辅助函数
int compare_exponents(const void *a, const void *b) {
    const Term *termA = a;
    const Term *termB = b;
    return termB- termA->exponent;
}

// 创建新项并添加到多项式
Term* add_term(Term *polynomial, int coefficient, int exponent) {
    Term *new_term = (Term*)malloc(sizeof(Term));
    new_term->coefficient = coefficient;
    new_term->exponent = exponent;
    if (!polynomial) {
        polynomial = new_term;
    } else {
        // 按照指数降序排列
        qsort(polynomial, sizeof(Term), sizeof(Term), compare_exponents);
        for (size_t i = 0; i < sizeof(polynomial)/sizeof(Term); ++i) {
            if (polynomial[i].exponent < exponent) {
                polynomial = realloc(polynomial, (i+2)*sizeof(Term));
                polynomial[i] = *new_term;
                break;
            }
        }
        if (polynomial[i].exponent == exponent) {
            polynomial[i].coefficient += coefficient;
        } else {
            polynomial[i+1] = *new_term;
        }
    }
    return polynomial;
}

// 打印多项式
void print_polynomial(Term *polynomial) {
    printf("n=%d: ", sizeof(polynomial)/sizeof(Term));
    for (size_t i = 0; i < sizeof(polynomial)/sizeof(Term); ++i) {
        printf("%d,%d, ", polynomial[i].coefficient, polynomial[i].exponent);
    }
    printf("\n");
}

int main() {
    Term *polynomial1 = NULL, *polynomial2 = NULL, *sum = NULL;
    int input1, input2, coefficient, exponent;

    // 输入并构建多项式
    while (scanf("%d,%d", &input1, &input2) == 2 && input1 != 0) {
        add_term(&polynomial1, input1, input2);
    }

    // 对第二个多项式做同样的操作
    scanf("%d,%d", &input1, &input2);
    add_term(&polynomial2, input1, input2);

    // 相加两个多项式
    sum = add_term(NULL, 0, 0);
    for (size_t i = 0; i < sizeof(polynomial1)/sizeof(Term); ++i) {
        sum = add_term(sum, polynomial1[i].coefficient, polynomial1[i].exponent);
    }
    for (size_t i = 0; i < sizeof(polynomial2)/sizeof(Term); ++i) {
        sum = add_term(sum, polynomial2[i].coefficient, polynomial2[i].exponent);
    }

    // 输出结果多项式
    print_polynomial(sum);

    free(polynomial1);
    free(polynomial2);
    free(sum);

    return 0;
}