Question

我正在写一些关于加密字符串的reddit代码挑战，我想出了类似的东西：

#include <iostream>
#include <string>

using namespace std;

string encrypt(string sentence);

int main()
{
    string sentence;
    int i = 0;
    cout << "Welcome. Enter a sentence: ";
    getline(cin, sentence);
    cout << sentence << endl;
    encrypt(sentence);
    cout << endl << endl;
    system("pause");
    return 0;
}

string encrypt(string sentence)
{

    int i = 0;
    int x = (sentence.size());
    string *encrypted_sentence = new string[sentence.size()];
    int *wsk = new int[sentence.size()];
    for (i = 0; i < x; i++)
    {
        wsk[i] = sentence[i];
    }

    for (i = 0; i < x; i++)
    {
        if (wsk[i] == ' ')
            continue;
        else if (islower(wsk[i]))
        {
            if (wsk[i] <= 99)
                wsk[i] = (wsk[i] + 23);
            else
                wsk[i] = (wsk[i] - 3);
        }
        else
        {
            if (wsk[i] <= 67)
                wsk[i] = (wsk[i] + 23);
            else
                wsk[i] = (wsk[i] - 3);
        }
    }
    for (i = 0; i < x; i++)
    {
        //cout << static_cast <char> (wsk[i]);
        encrypted_sentence[i] = wsk[i];
    }

    return *encrypted_sentence;
}

我的问题是，没有任何东西可以归还。在我运行程序后，我得不到任何回报。有人能指出我正确的方向吗？我错过了什么？

Answer 1

首先main()会返回int 始终。 void main()不标准。其次：

string encrypted_sentence = new string[sentence.size()];

甚至不会编译。 encrypted_sentence类型为std::string，但您尝试为其分配std::string *。第三个you should avoid using using namespace std;

<强>更新

我相信您正在尝试输出加密字符串：

cout << endl << endl;

但所有这一切都是输出2个换行符并刷新输出两次。如果要显示加密的字符串，则需要捕获encrypt()函数的返回值并显示它，或encrypt()可以通过引用获取字符串。如果您更改encrypt()以获取参考，那么它将变为：

void encrypt(string & sentence)
{
    string *encrypted_sentence = new string[sentence.size()]; // get rid of this line as it is not needed.
    //...
    for (i = 0; i < x; i++)
    {
        sentence[i] = wsk[i];
    }
}

然后你输出字符串：

cout << sentence << endl;

Answer 2

如果有人想要回答这个问题，我会想出这个问题，我很确定它最终会按照我想要的方式运作：

#include <iostream>
#include <string>

std::string encrypt(std::string to_encrypt);

int main()
{
std::string sentence;
std::string result;
std::cout << "Welcome. Please enter a sentence: ";
getline(std::cin, sentence);
result = encrypt(sentence);
std::cout << "Result: " << result << std::endl;
system("pause");
return 0;
}

std::string encrypt(std::string to_encrypt)
{
int i = 0;
int x = (to_encrypt.size());
std::cout << std::endl << "x = " << x << std::endl;
int *temp = new int[to_encrypt.size()];
for (i = 0; i < x; i++)
{
    temp[i] = to_encrypt[i];
}

for (i=0; i < x; i++)
{
    if (temp[i] == ' ')
        continue;
    else if (islower(temp[i]))
    {
        if (temp[i] <= 99)
            temp[i] = temp[i] + 23;
        else
            temp[i] = temp[i] - 3;
    }
    else
    {
        if (temp[i] <= 67)
            temp[i] = temp[i] + 23;
        else
            temp[i] = temp[i] - 3;
    }
}
std::string encrypted;
for (i = 0; i < x; i++)
{
    encrypted += (static_cast <char> (temp[i]));
}
return encrypted;

}

Answer 3

代码显然是错误的。 string * encrypted_sentence = new string [sentence.size（）];分配ARRAY字符串！不是一个字符串。从这一点来看，你可以看到你的代码是错误的。

无法从函数返回动态字符串

3 个答案: