我们能把NSArray转换成c数组吗?如果不是,我需要在opengl函数中提供c数组,其中c数组包含从there.suppose文件读取的顶点指针。
发布于 2009-06-18 10:22:51
答案取决于C数组的性质。
如果您需要填充一个已知长度的原始值数组,您可以这样做:
NSArray* nsArray = [NSArray arrayWithObjects:[NSNumber numberWithInt:1],
[NSNumber numberWithInt:2],
nil];
int cArray[2];
// Fill C-array with ints
int count = [nsArray count];
for (int i = 0; i < count; ++i) {
cArray[i] = [[nsArray objectAtIndex:i] intValue];
}
// Do stuff with the C-array
NSLog(@"%d %d", cArray[0], cArray[1]);
下面是一个示例,我们想要从一个NSArray
创建一个新的C数组,并将数组项保留为Obj-C对象:
NSArray* nsArray = [NSArray arrayWithObjects:@"First", @"Second", nil];
// Make a C-array
int count = [nsArray count];
NSString** cArray = malloc(sizeof(NSString*) * count);
for (int i = 0; i < count; ++i) {
cArray[i] = [nsArray objectAtIndex:i];
[cArray[i] retain]; // C-arrays don't automatically retain contents
}
// Do stuff with the C-array
for (int i = 0; i < count; ++i) {
NSLog(cArray[i]);
}
// Free the C-array's memory
for (int i = 0; i < count; ++i) {
[cArray[i] release];
}
free(cArray);
或者,您可能希望对数组执行nil
-terminate操作,而不是传递其长度:
// Make a nil-terminated C-array
int count = [nsArray count];
NSString** cArray = malloc(sizeof(NSString*) * (count + 1));
for (int i = 0; i < count; ++i) {
cArray[i] = [nsArray objectAtIndex:i];
[cArray[i] retain]; // C-arrays don't automatically retain contents
}
cArray[count] = nil;
// Do stuff with the C-array
for (NSString** item = cArray; *item; ++item) {
NSLog(*item);
}
// Free the C-array's memory
for (NSString** item = cArray; *item; ++item) {
[*item release];
}
free(cArray);
发布于 2009-06-18 15:33:10
NSArray
有一个用于为数组的子范围创建C数组的-getObjects:range:
方法。
示例:
NSArray *someArray = /* .... */;
NSRange copyRange = NSMakeRange(0, [someArray count]);
id *cArray = malloc(sizeof(id *) * copyRange.length);
[someArray getObjects:cArray range:copyRange];
/* use cArray somewhere */
free(cArray);
发布于 2009-06-18 09:43:20
我建议你改变自己的想法,比如:
NSArray * myArray;
... // code feeding myArray
id table[ [myArray count] ];
int i = 0;
for (id item in myArray)
{
table[i++] = item;
}
https://stackoverflow.com/questions/1011711
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