Help me with files in C

Question

Why does this work?
1)
#include <stdio.h>
void main()
{
FILE *fptr=fopen("/storage/emulated/0/Cxxdroid/Fileoperations/myfile.txt","r");
char str1[20];
fgets(str1,20,fptr);
printf("%s",str1);
}
But this doesn't?
2)
#include <stdio.h>
void main()
{
FILE *fptr=fopen("/storage/emulated/0/Cxxdroid/Fileoperations/myfile.txt","r");
char* str1;
fgets(str1,20,fptr);
printf("%s",str1);
}

Answer 1

For the second snippet, you must initialize <str1> using either malloc() or calloc() before you can use it as buffer for reading data.
And use free() afterwards, to release the allocated memory block once you are done using it.
http://www.cplusplus.com/reference/cstdlib/malloc/
http://www.cplusplus.com/reference/cstdlib/calloc/
http://www.cplusplus.com/reference/cstdlib/free/

Answer 2

Ipang oh yes yes now it works. Thank you so much✌️✌️✌️