用 char 遍历 char 数组出错

Question

我想用 char 数组中的 char 进行迭代（但我用字符串构建它）并在字符 == 迭代字符串时打印该字符。但是，第一个打印的字符与所需的字符串不同。而且它有时会在结尾添加一个意想不到的字符。

预期输出：

我是史蒂夫

输出：

~我是史蒂夫

我正在尝试让控制台使用迭代字符串打印输出，我的意思是这样的：

A

首先，控制台打印A，然后我执行回车，正如您在第 14 行看到的那样，然后转到B，直到输出是所需字符串的第一个字符。 如果输出的字符与字符相同，则将其放入数组cmem。它继续迭代第二个字符，依此类推。

代码如下：

#include <iostream>
using namespace std;
//starts here!
int main(){
    char hlw[] = "I am Steve.";
    char j; //to be iterated.
    int hlwstrlen = strlen(hlw);
    char cmem[hlwstrlen]; //memorize the correct char.
    char convertedChar; //converted char
    //iterating begin
    for (int ch = 0; ch <= hlwstrlen; ch++){
        for (int aschr = 32; aschr <= 126; aschr++){
            convertedChar = static_cast<char>(aschr); //this converts to an ascii from an int.
            cout <<  convertedChar << "\r";
            if(convertedChar == hlw[ch]){
                cout << convertedChar << "\r";
                cmem[ch] = convertedChar;

                for(int i = 0; i <= ch; i++){
                    cout << cmem[i];
                }
                continue;

             }
         }
    }
cout << endl;
return 0;
}

注意：如果我不能完美地格式化代码，我很抱歉。我用手机打字。

Answer 1

#include <string>
#include <iostream>
#include <algorithm> // remove_copy_if
#include <cctype> // isprint, isalpha, isalnum, ispunct

// you check for these characters.
// I suspect you may want std::isprint, instead.
bool custom_exclude_filter(char c) {
    return c < 32 || c > 126;
}

int main() {
    // since you are trying to filter out bad characters,
    // let's put a bad character in the actual string
    char hlw[] = "I am \x010Steve.";
    std::string s(hlw, sizeof(hlw));

    // print only the printable characters
    for (auto c : s) {
        if (std::isprint(c))
            std::cout << c;
    }
    std::cout << std::endl;

    // works the same on hlw. The compiler knows its size already.
    for (auto c : hlw) {
        if (std::isprint(c))
            std::cout << c;
    }
    std::cout << std::endl;

    // same thing using your custom filter
    for (auto c : s) {
        if (!custom_exclude_filter(c))
            std::cout << c;
    }
    std::cout << std::endl;

    // Make a new string using only printable characters,
    // using std algorithm, and print the string
    {
        std::string temp_string;
        std::remove_copy_if(s.begin(), s.end(), std::back_inserter(temp_string), [](char c) {return 0 == std::isprint(c); });
        std::cout << temp_string << std::endl;
    }

    // you can iterate a string literal, using std::begin and std::end
    // see https://stackoverflow.com/a/13207440/1766544
    {
        std::string temp_string;
        std::remove_copy_if(std::begin(hlw), std::end(hlw), std::back_inserter(temp_string), [](char c) {return 0 == std::isprint(c); });
        std::cout << temp_string << std::endl;
    }

    // same thing using your custom filter
    {
        std::string temp_string;
        std::remove_copy_if(s.begin(), s.end(), std::back_inserter(temp_string), custom_exclude_filter);
        std::cout << temp_string << std::endl;
    }
}

Answer 2

我用了之前在这里评论过的人的代码，忘记是谁了，也不知道为什么所有的cmets都被删除了。而且效果很好！感谢之前帮助过我的各位！

#include <iostream>

using namespace std;

int main(){
    const char hlw[] = "I am Steve"; //Declare collection of char
    const int hlwstrlen = strlen(hlw);
    char *cmem = new char[hlwstrlen];
    char convertedChar;
    int len = 0;

     for (int ch = 0; ch < hlwstrlen; ch++){

        for (int aschr = 32; aschr <= 126; aschr++){

            const char convertedChar = static_cast<char>(aschr);

            cout << convertedChar << "\r";

            if (convertedChar == hlw[ch]){

                cmem[len++] = convertedChar;

                continue;

            }       
        }
    }
cout << cmem << '\n';

delete[] cmem;
cout << endl;

return 0;
}