C++和C的转换问题

[liqian99]

C++语句如下:
unsigned char ** buffer;

buffer = new unsigned char * [height];
buffer[0] = new unsigned char[height * width];

上述两个转成纯C应怎样写,有点不太清楚其区别,哪位在虾帮忙指点一下.

[晨星]

unsigned char ** buffer;

buffer = (char**)malloc(height * sizeof(char*));
buffer[0] = (char*)malloc(height * width * sizeof(char));
差不多就是这个样子吧。

只是很奇怪为什么第二次还要再乘一个height？难道实际上是三维？

[bargio_susie]

不清楚C++语法。。我试着理解下，楼下的纠正。

unsigned char ** buffer;

buffer = ( unsigend char **)malloc(sizeof(unsigend char) * height );
buffer[0] = ( unsigend char *)malloc(sizeof(unsigend char) * height * width );

[bargio_susie]

没看到楼上的，学习了。。

[晨星]

哦，写错了。
楼上的对，应该是unsigned char

[liqian99]

三楼的正确,编译通过了,谢谢了.怎样给分?

[WinWing]

点右上角的管理就可以了

[haichuan1988]

我怎么不能提问了

[liqian99]

还是不对,分配后处理会报错.

[diclover]

unsigned char ** buffer;

buffer = ( unsigend char **)malloc(sizeof(unsigend char［ height］ );
buffer[0] = ( unsigend char *)malloc(sizeof(unsigend char［height * width ］);

这样就可以了

[diclover]

少个反括号：
unsigned char ** buffer;

buffer = ( unsigend char **)malloc(sizeof(unsigend char［ height］ )）;
buffer[0] = ( unsigend char *)malloc(sizeof(unsigend char［height * width ］)）;

[WinWing]

有没有用到后面的内存啊?
改成这样:
unsigned char ** buffer;

buffer = ( unsigend char **)malloc(sizeof(unsigend char［ height］ );
for(int i=0;i<height*width;i++)
buffer[i] = ( unsigend char *)malloc(sizeof(unsigend char［height * width ］);

[WinWing]

同样奇怪为什么要height*width

[windeflower]

三楼的稍微改下就哦了。第一个语句应该sizeof(unsigend char*)而不是sizeof(unsigend char)

unsigned char ** buffer;

buffer = ( unsigend char **)malloc(sizeof(unsigend char*) * height );
buffer[0] = ( unsigend char *)malloc(sizeof(unsigend char) * height * width );

[qrg04201111]

为什么要height*width呢?不明白...解释一下麻烦(新手)