Struct open binary file C

#include <stdio.h>
#include <stdlib.h>
struct source_files{
FILE *fpt;
char *path;
int stat;
};
void open_struct_file(
struct source_files *da){
printf("in fun %s\n",da->path);
da->fpt=fopen(da->path,"ab+");
if(!da->fpt)
da->stat=0; // false
else
da->stat=1; // true
}
int main(int argc, char **argv){
struct source_files sf;
char *path;
if(argc==1){
sf.path="data.dat";
open_struct_file(&sf);
    if(sf.stat){
        printf("file open %d\n",sf.stat);
    }else{
        printf("file not open %d\n",sf.stat);
        exit(1);
    }
}
else if (argc==2){
path=strdup(argv[1]);
//printf("%s\n",path);
FILE *ff = fopen(path,"ab+");
    if(!ff){
        printf("file not open\n");
        exit(1);
    }else{
        printf("file open\n");
    }
}
return 0;
}