改過的code

#include <stdio.h>
#include <string.h>

#define MAX_SIZE 500

char content[MAX_SIZE];
char input[MAX_SIZE];
char tmp[MAX_SIZE];
char com[4][20] = {"/backspace", "/newline", "/left", "/right"};
int ans_index = 0;

void shift()
{
    int l = strlen(content);
    for (int i = l; i > ans_index; i--)
    {
        content[i] = content[i - 1];
    }
    return;
}

int check()
{
    for (int i = 0; i < 4; i++)
    {
        if (strcmp(tmp, com[i]) == 0)
        {
            if (i == 0 && ans_index > 0)
            {
                ans_index--;
                int l = strlen(content);
                for (int j = ans_index; j < l; j++)
                {
                    content[j] = content[j + 1];
                }
            }
            else if (i == 1)
            {
                if (content[ans_index] != '\0')
                    shift();
                content[ans_index] = '\n';
                ans_index++;
            }
            else if (i == 2)
            {
                if (ans_index > 0)
                {
                    ans_index--;
                }
            }
            else if (i == 3)
            {
                if (ans_index < strlen(content))
                {
                    ans_index++;
                }
            }
            return 1;
        }
    }
    return 0;
}

int main()
{
    //freopen("test.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);

    fgets(input, MAX_SIZE, stdin);
    memset(content, '\0', MAX_SIZE);

    int len = strlen(input);
    int mode = 0, index = 0;

    for (int i = 0; i < len; i++)
    {
        if (input[i] == '/')
        {
            mode = 1;
        }
        if (mode == 0 && input[i] != '\n')
        {
            if (content[ans_index] != '\0')
            {
                shift();
            }
            content[ans_index] = input[i];
            ans_index++;
        }
        else if (mode == 1)
        {
            tmp[index] = input[i];
            index++;
            if (check() == 1)
            {
                mode = 0, index = 0;
                memset(tmp, '\0', sizeof(tmp));
            }
        }
    }
    for (int i = 0; i < strlen(content); i++)
    {
        printf("%c", content[i]);
    }

    return 0;
}