在建立一个一元一次多项式程序的基础上，增加以下功能。 ①建立一个函数，计算并返回一元多项式中一共有多少项数据。 ②建立一个函数，可以得到一元多项式中指数最大元素的系数并打印出来。 ③ 建立一个函数，输人系数和指数，如果元素存在，则删除之，否则打印出错信息。使用c语言。

在C语言中，为了实现这些功能，你可以创建一个结构体`Polynomial`来表示一元多项式的各项，包括系数和指数。下面是一个简单的实现：

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

typedef struct {
    double coefficient;
    int exponent;
} Term;

// 1. 计算一元多项式的项数
Term* createTerm(double coef, int exp) {
    Term* newTerm = (Term*)malloc(sizeof(Term));
    if (newTerm != NULL) {
        newTerm->coefficient = coef;
        newTerm->exponent = exp;
    }
    return newTerm;
}

size_t countTerms(Term* polynomial) {
    size_t termCount = 0;
    while (polynomial != NULL) {
        termCount++;
        polynomial = polynomial->next;
    }
    return termCount;
}

// 2. 获取指数最大的项的系数
double getMaxCoefficient(Term* polynomial) {
    double maxCoef = -INFINITY; // 初始化为负无穷大
    Term* current = polynomial;
    while (current != NULL) {
        if (current->coefficient > maxCoef && current->exponent > 0) { // 确保只有正指数才考虑
            maxCoef = current->coefficient;
        }
        current = current->next;
    }
    return maxCoef;
}

// 3. 删除特定系数和指数的项或打印错误
void deleteTerm(Term** polynomial, double coefficient, int exponent) {
    Term* prev = NULL;
    Term* current = *polynomial;
    while (current != NULL) {
        if (current->coefficient == coefficient && current->exponent == exponent) {
            if (prev == NULL) {
                *polynomial = current->next;
            } else {
                prev->next = current->next;
            }
            free(current);
            break;
        } else {
            prev = current;
            current = current->next;
        }
    }
    if (current == NULL) {
        printf("Error: Element not found.\n");
    }
}

int main() {
    Term* polynomial = createTerm(2.0, 1); // 示例多项式: 2x^1
    polynomial = createTerm(-3.5, 2); // 添加项: -3.5x^2
    polynomial->next = createTerm(1.75, 0); // 添加常数项: 1.75

    printf("The polynomial has %zu terms.\n", countTerms(polynomial));
    printf("The coefficient of the highest exponent is %.2f.\n", getMaxCoefficient(polynomial));

    double coefficientToDelete = 2.0;
    int exponentToDelete = 1;
    deleteTerm(&polynomial, coefficientToDelete, exponentToDelete);

    return 0;
}