如何在C ++中将字符串转换为char *？ [英] How to convert string to char * in C++?

问题描述

如何将字符串转换为 char * 我正在使用以下方法，但它没有工作。

How can I convert a string in to char * I was using the following method, but it doesn't work.

在运行时出现以下错误：

At runtime it gives me the following error:

运行时检查失败＃3-使用变量'url'时未初始化
。

Run-Time Check Failure #3 - The variable 'url' is being used without being initialized.

尽管我已将其初始化，如图所示在下面的代码中。

eventhough I have initialized it as shown in the code bellow. Can you please show me with an example?

    char* url;
    sup = "news"
    sup="http://www."+sup+"yahoo.com";
    strcpy(url, sup.c_str());

我在控制台中使用Microsoft Visual Studio 2010和C ++

I am using Microsoft Visual Studio 2010, C++ in console

推荐答案

strcpy 不会为您分配内存，您必须自己做，记住要为null留出空间终止符：

strcpy doesn't allocate memory for you, you must do it yourself, remembering to leave space for the null termination character:

char* url = new char[sup.length()+1];

或

char url[sup.length()+1];
//...
strcpy(url, sup.c_str());

在第一种情况下，请不要忘记删除[] 数组。仅当您的编译器支持C99可变长度数组作为扩展名时，第二种情况才有效。

In the first case, don't forget to delete[] the array. The second case will only work if your compiler supports C99 variable-length arrays as an extension.

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