c++ - 使用指针从 char array[] 中移除/删除字符

Question

我需要帮助从 char 数组中删除空格和特殊字符。我一直遇到的问题是删除函数只适用于字符串数据类型，如果我没记错的话。赋值需要一个 char 数组而不是一个字符串，所以我不能只转换它或有一个字符串变量。我试过查找它，但一切都只是建议将其转换为字符串或以字符串开始，我做不到。我是编程新手，指针对我来说有点奇怪，所以如果答案很明显，我很抱歉。

    #include "stdafx.h"
    #include <iostream>
    #include <stdio.h>
    #include <string>
    #include <stdlib.h>
    #include <ctype.h>
    using namespace std;
        
           int main()
            {
                const int SIZE = 80;
                char str[SIZE];
                char* strPtr;
                int strlength;
                int j = 0;
                int front = 0, back; int flag = 1;
                
                strPtr = str;
            
                cout << "This program checks for palidromes." << endl;
                cout << "Please enter a phrase." << endl;
                cout << endl;
                cin.getline(str, SIZE);
            
                //Get the length of string str
            
                strlength = strlen(str);
            
                //Convert all the characters in the string str to uppercase
                for (int i = 0; i < strlength; i++)
                {
                    if (!isupper(str[i]))
                        str[i] = toupper(str[i]);
                }   
            
                //Remove all the special characters except letters a - z
                for (int i = 0; i < strlength; i++)
            
                    if (!isalpha(str[i])||(!isalnum(str[i])))
                    {
                        str.erase(str[i]); // need help here. Not sure how to go about it.
                    }
            
                //str[j] = '\0';
                
                return 0;
            }

Answer 1

char* tail = std::remove_if(str, str + strlength,
    [](char c){ return !isalpha(c)||(!isalnum(c)); });
strlength = tail - str;
*tail = 0;