implicitly declaring function 'malloc' with type void *(unsigned long ) 错误解决

errror : implicitly declaring function ‘malloc‘ with type void *(unsigned long )

Be sure to include the correct header file.
```
#include <stdlib.h>
```
Casting the return is allowed but frowned upon in C as being unnecessary.
```
double* sequence = malloc(...);
```
Consider the follow style as its easier to maintain and IMO, less error prone.
```
double* sequence = malloc(numInSeq * sizeof(* sequence));
```
Remember the argument type is size_t may differ in size than int. size_t is the unsigned integer type of the result of the sizeof operator.
```
void *malloc(size_t size);
```

Check the result.

if (sequence == NULL) Handle_OutOfMemory();

Eventually, free the pointer. It is OK to free the pointer even if it has a NULL value.
```
free(sequence);
```
If there is a chance sequence will get used agian, best to promptly set its value to NULL.
```
free(sequence);
sequence = NULL;
```

implicitly declaring function 'malloc' with type void *(unsigned long ) 错误 解决