convert Ascii code file into binary file - c

Question

I have a problem of converting ASCII code file into binary file. The code is able to read file and print data into other file as ASII code ( using fprintf); however, when I try to convert from ASII code to binary file ( using fwrite), and then use (fread) the file again. It doesn't generate the right answer. My doubt is the fwrite function doesn't work probably. Could you please advise on how to fix this problem? Thank you very much.
============================================
Code to convert from ASCII to binary file
===========================================
# include <stdio.h>
# include <stdlib.h>
# include <string.h>
typedef struct _FileData
{
int a;
double b;
char dataStr[56];
}FileData;
int main()
{
// open read file
FILE * infile=fopen("output.txt", "r");
if(infile==NULL)
{
printf("Error opening file");
exit(1);
}
// open write file
FILE * outfile = fopen("out_file.txt","wb");
if( outfile==NULL)
{
printf("Error writting on file");
exit(1);
}
FileData input; // pointer for read file
FileData output; // pointer for write file
while( fscanf(infile,"%d %lf %[^\n]s",&input.a,&input.b,&input.dataStr)==3)
{
/*printf("%d\n",input.a);
printf("%.3lf\n",input.b);
printf("%s\n",input.dataStr);*/
//fprintf(outfile,"%d\n %.3lf\n %s\n",input.a,input.b,input.dataStr);
fwrite(&output,sizeof(FileData),1,outfile);
}
fclose(infile);
fclose(outfile);
return 0;
}
==============================================================
Code to convert from binary file to ASCII code file
=============================================================
# include <stdio.h>
# include <stdlib.h>
# include <string.h>
typedef struct FileData
{
int a;
double b;
char dataStr[56];
}FileData;
int main()
{
FILE * infile=fopen("out_file.txt", "rb");
if(infile==NULL)
{
printf("Error opening file");
}
FileData input;
while(fread(&input,sizeof(struct FileData),sizeof(struct FileData),infile))
{
printf("%d\n",input.a);
printf("%.3f\n",input.b);
printf("%s\n",input.dataStr);
}
return 0;
}
===========================================================
Data
==========================================================
47
34.278
This is a line of text
48
23.678
This a very very long line

Answer 1

fread(&input,sizeof(struct FileData),sizeof(struct FileData),infile)
should be changed to
fread(&input,sizeof(struct FileData),1,infile)
You want to write 1 struct of size sizeof(struct FileData)
Also check the answer of mash5 where he suggests writing variable input instead of output while writing with fwrite.

Answer 2

In your ASCII conversion code, the input file is read into one variable input
fscanf(infile,"%d %lf %[^\n]s",&input.a,&input.b,&input.dataStr)
but a different, uninitialized, variable output is being written to the output file:
fwrite(&output,sizeof(FileData),1,outfile);
Perhaps you should write
fwrite(&input,sizeof(input),1,outfile);
instead?