C语言 错误：初始化使指针从整数而不进行强制转换
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Error: initialization makes pointer from integer without a cast
提问by user3422805
I have had trouble with this piece of code returning the error:
我在这段代码返回错误时遇到了麻烦：
assgTest2.c: In function 'Integrate':
assgTest2.c:12: warning: initialization makes pointer from integer without a cast
assgTest2.c:15: error: expected ';' before ')' token
I've had a look around and haven't been able to make sense of the answer to similar questions, any help would be appreciated.
我环顾四周，无法理解类似问题的答案，任何帮助将不胜感激。
1 void SamplePoint(double *point, double *lo, double *hi, int dim)
2 {
3 int i = 0;
4 for (i = 0; i < dim; i++)
5 point[i] = lo[i] + rand() * (hi[i] - lo[i]);
6 }
7
8 double Integrate(double (*f)(double *, int), double *lo, double *hi, int dim,
9 double N)
10 {
11 double * point = alloc_vector(dim);
12 double sum = 0.0, sumsq = 0.0;
13
14 int i = 0;
15 for (i = 0.0, i < N; i++)
16 {
17 SamplePoint(point, lo, hi, dim);
18
19 double fx = f(point, dim);
20 sum += fx;
21 sumsq += fx * fx;
22 }
23
24 double volume = 1.0;
25 i = 0;
26 for (i = 0; i < dim; i++)
27 volume *= (hi[i] - lo[i]);
28
29 free_vector(point, dim);
30 return volume * sum / N;
31 }
Edit: Fixed some mistakes, still giving the same error
编辑：修正了一些错误，仍然给出同样的错误
回答by pmg
I guess this is your line 12
我猜这是你的第 12 行
double * point = alloc_vector(dim);
The text of the warning is
警告的文本是
warning: initialization makes pointer from integer without a cast
What this means is that the integer returned from alloc_vector()is being automatically converted to a pointer and you shouldn't do that (also you should not cast despite what the warning hints at).
这意味着从返回的整数将alloc_vector()自动转换为指针，您不应该这样做（尽管警告提示，您也不应该强制转换）。
Correction: add the proper #includewhere alloc_vector()is declaredso that the compiler knows it returns a pointer and doesn't need to guess (incorrectly) it returns an integer.
更正：添加正确的#includewherealloc_vector()声明，以便编译器知道它返回一个指针并且不需要猜测（错误地）它返回一个整数。
Or, if you don't have the include file, add the prototype yourself at the top of your file
或者，如果您没有包含文件，请自己在文件顶部添加原型
double *alloc_vector(int); // just guessing
line 15
第 15 行
for (i = 0.0, i < N; i++)
The text for the error is
错误的文本是
assgTest2.c:15: error: expected ';' before ')' token
Each for statement has two semicolons in the control structure (between parenthesis). Your control structure only has 1 semicolon. Change that to
每个 for 语句在控制结构中都有两个分号（在括号之间）。您的控制结构只有 1 个分号。将其更改为
for (i = 0.0; i < N; i++)
// ^ <-- semicolon
