[英]Allocating memory for array in struct (in C)
I need to define a type-struct in C that contains an array to be malloc'd as: 我需要在C中定义一个包含要被malloc为的数组的类型结构:
#include <stdio.h>
#include <stdlib.h>
typedef struct mine
{
int N;
double *A;
} mine;
int main(int argc, char** argv)
{
int i;
mine *m=malloc(sizeof(mine));
printf("sizeof(mine)=%d\n",sizeof(mine));
scanf("Enter array size: %d",&(m->N));
m->A=malloc((m->N)*sizeof(double));
for(i=0; i < m->N; i++)
m->A[i]=i+0.23;
printf("First array element: %lf",m->A[0]);
return (EXIT_SUCCESS);
}
The program compiles and runs, and the integer assignment seems to work fine. 程序编译并运行,整数赋值似乎工作正常。 The array is not working as it should, however. 但是,该阵列不能正常工作。
Any suggestions? 有什么建议么? I would like m to remain a pointer (to pass to functions etc.). 我想米仍然是一个指针(传递给功能等)。
Thanks. 谢谢。
This is your problem: 这是你的问题:
scanf("Enter array size: %d",&(m->N));
It should be two separate steps: 它应该是两个单独的步骤:
printf("Enter array size: ");
scanf("%d",&(m->N));
(and for debugging checking:) (以及调试检查:)
printf("The size entered appears to be %d\n", m->N);
That way, you know if you got the value you intended to get! 那样,你知道你是否得到了你想要获得的价值!
如果@abelenky回答你的问题很好,但我总是被告知要从void *中投出malloc的结果,它会返回到你实际使用的任何东西。
mine *m = (mine *)malloc(sizeof(mine));
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