将一个中缀表达式，转换为后缀表达式 转换成C语言代码

很高兴为您提供帮助，以下是C语言代码：

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

#define MAX_STACK_SIZE 100

typedef enum {
    lparen, rparen, plus, minus, times, divide, mod, eos, operand
} precedence;

int stack[MAX_STACK_SIZE];
char expr[MAX_STACK_SIZE];
int top = -1;

precedence get_token(char* symbol, int* n);
void push(int item);
int pop(void);
void print_token(precedence token);

int main() {
    int n = 0;
    char symbol;
    precedence token;

    printf("Enter an infix expression: ");
    while ((symbol = getchar()) != '\n') {
        expr[n++] = symbol;
    }
    expr[n] = '\0';

    printf("The postfix expression is: ");
    token = get_token(&symbol, &n);
    while (token != eos) {
        if (token == operand) {
            printf("%c", symbol);
        }
        else if (token == rparen) {
            while (stack[top] != lparen) {
                print_token(pop());
            }
            pop();
        }
        else {
            while (stack[top] != eos && stack[top] >= token) {
                print_token(pop());
            }
            push(token);
        }
        token = get_token(&symbol, &n);
    }
    while ((token = pop()) != eos) {
        print_token(token);
    }
    printf("\n");

    return 0;
}

precedence get_token(char* symbol, int* n) {
    *symbol = expr[(*n)++];
    switch (*symbol) {
        case '(': return lparen;
        case ')': return rparen;
        case '+': return plus;
        case '-': return minus;
        case '*': return times;
        case '/': return divide;
        case '%': return mod;
        case '\0': return eos;
        default: return operand;
    }
}

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

int pop() {
    if (top == -1) {
        fprintf(stderr, "Stack underflow\n");
        exit(EXIT_FAILURE);
    }
    return stack[top--];
}

void print_token(precedence token) {
    switch (token) {
        case lparen: printf("("); break;
        case rparen: printf(")"); break;
        case plus: printf("+"); break;
        case minus: printf("-"); break;
        case times: printf("*"); break;
        case divide: printf("/"); break;
        case mod: printf("%%"); break;
        default: break;
    }
}