搅拌长度计算 [英] Stirng Length Calculation

问题描述

我想在visual studio 2008中使用此代码计算字符串长度，代码为

I want to calculate string length using this code in visual studio 2008,the code is

void main(){
      char *str;
      int count = 0,i;
      
      printf("\nEnter the String: ");
      gets(str);
      for(i=0;str[i]!='\0';i++){
            count++;
      }
      printf("\nThe length of the string is %d.",count);
      getch();
}

但我收到错误

but I am getting error

"Unhandled exception at 0x6a4794af (msvcr90d.dll) : 0xC0000005: Access violation writing location 0x013f575d."

如何解决请帮助

[更新]

How to solve please help
[Updated]

void main(){
      char *str="";
      int count = 0,i;

      printf("\nEnter the String: ");
      gets(str);
      for(i=0;str[i]!='\0';i++){
            count++;
      }
      printf("\nThe length of the string is %d.",count);
      getch();
}

但是它给出了同样的错误请帮助

but it giving same error please help

推荐答案

你要去找一个未初始化的指针。因此尝试将其输出写入一些奇怪的内存位置。这就是访问违规的来源。



为您要读取的行分配缓冲区并传递该缓冲区以获取，例如：

You are passing to gets an uninitialized pointer. So gets tries to write its output to some weird memory location. That''s what the "Access violataion" comes from.

Allocate a buffer for the line that you want to read and pass that buffer to gets, for example:

char lineBuffer[200];
gets (lineBuffer);

正如您在C ++中获得更高级时的一个注释：有更好的方法来读取一行而不是获取。得到的缺点是你不能告诉它，你的缓冲区有多长;如果你的输入足够长，它会覆盖缓冲区结束并破坏你的记忆。

Just as a note for the time when you are getting more advanced in C++: There are better ways to read a line than gets. gets has the disadvantage that you can''t tell it, how long your buffer is; and if your input is long enough it therefore overwrites the buffer end and corrupts your memory.

这是因为你声明和使用 str <的方式/ code> - 您的代码中没有分配内存。

请参阅此处的示例cplusplus.com参考 [ ^ ]对于一种方法，但你最好使用fgets看看



这篇文章 [ ^ ]使用该建议

It''s because of the way you are declaring and using str - there is no memory allocated to it in your code.
See the example here cplusplus.com reference[^] for one way of doing it but you would be better off using fgets see

this post [^] for a suggestion using that

看起来你正在传递一个未初始化的指针获取。



尝试更换生产线

char * str;



with

char str [81]; // 80个字符的空间+''\ 0''



看看这是否能让你更进一步。

It looks like you''re passing an uninitialized pointer to gets.

Try replacing the line
char* str;

with
char str[ 81 ]; //room for 80 chars + ''\0''

See if this gets you any further.

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