输入一个中缀算术表达式，将其转换为后缀表达式，然后对后缀表达式进行求值。用c语言怎么写

下面是一个用C语言实现将中缀表达式转换为后缀表达式并求值的程序：

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

#define MAXSTACK 100
#define EMPTYSTACK -1
#define EOS '\0'

typedef enum { false, true } bool;

int stack[MAXSTACK];
int top = EMPTYSTACK;

void push(int token) {
    if (top >= MAXSTACK - 1) {
        fprintf(stderr, "Stack overflow\n");
        exit(EXIT_FAILURE);
    } else {
        top++;
        stack[top] = token;
    }
}

int pop() {
    if (top == EMPTYSTACK) {
        fprintf(stderr, "Stack underflow\n");
        exit(EXIT_FAILURE);
    } else {
        return stack[top--];
    }
}

int precedence(char operator) {
    switch (operator) {
        case '(':
            return 0;
        case '+':
        case '-':
            return 1;
        case '*':
        case '/':
            return 2;
        default:
            return -1;
    }
}

void convert(char infix[], char postfix[]) {
    int i = 0, j = 0, token;
    char symbol;
    for (i = 0; infix[i] != EOS; i++) {
        symbol = infix[i];
        if (isdigit(symbol)) {
            postfix[j++] = symbol;
        } else if (symbol == '(') {
            push(symbol);
        } else if (symbol == ')') {
            while ((token = pop()) != '(') {
                postfix[j++] = token;
            }
        } else {
            while (precedence(symbol) <= precedence(stack[top]) && top != EMPTYSTACK) {
                token = pop();
                postfix[j++] = token;
            }
            push(symbol);
        }
    }
    while (top != EMPTYSTACK) {
        token = pop();
        postfix[j++] = token;
    }
    postfix[j] = EOS;
}

int evaluate(char postfix[]) {
    int i = 0, op1, op2, token;
    char symbol;
    for (i = 0; postfix[i] != EOS; i++) {
        symbol = postfix[i];
        if (isdigit(symbol)) {
            push(symbol - '0');
        } else {
            op2 = pop();
            op1 = pop();
            switch (symbol) {
                case '+':
                    token = op1 + op2;
                    break;
                case '-':
                    token = op1 - op2;
                    break;
                case '*':
                    token = op1 * op2;
                    break;
                case '/':
                    token = op1 / op2;
                    break;
                default:
                    fprintf(stderr, "Invalid operator\n");
                    exit(EXIT_FAILURE);
            }
            push(token);
        }
    }
    token = pop();
    if (top != EMPTYSTACK) {
        fprintf(stderr, "Stack not empty\n");
        exit(EXIT_FAILURE);
    }
    return token;
}

int main() {
    char infix[MAXSTACK], postfix[MAXSTACK];
    printf("Enter an infix expression: ");
    fgets(infix, MAXSTACK, stdin);
    convert(infix, postfix);
    printf("Postfix expression: %s\n", postfix);
    printf("Result: %d\n", evaluate(postfix));
    return 0;
}

程序中的`convert()`函数将中缀表达式转换为后缀表达式，`evaluate()`函数对后缀表达式进行求值。在`main()`函数中，读入一个中缀表达式，将其转换为后缀表达式并输出，然后对后缀表达式进行求值并输出结果。