Add blockquote to a c file

#include"stdio.h"
#include"stdlib.h"

/****
Read in a file as input file.c
whenever you encounter '{', replace it with '{blockquote_begin'
whenever you encounter '}', replace it with 'blockquote_end}'
write output to file file.c.blog
****/

int main(int argc, char ** argv)
{

char *fout;
FILE *in, *out;
int len,c;
if ( argc == 2 )
{

in = fopen(argv[1],"r");
if(in==NULL)
{

printf("open file %s failed!\n",argv[1]);
return 1;

}
len=strlen(argv[1])+1+5;
fout=malloc(sizeof(*fout)*(len+1+5));
strcpy(fout,argv[1]);
strcat(fout,".blog");
out = fopen(fout,"w");
if(out==NULL)
{

printf("open file %s failed!\n",fout);
return 1;

}
printf ("in %s\nout %s\n",argv[1],fout);

}
else
{

printf("Usage: \n");
printf("%s \n",argv[0]);
return 2;

}

do
{

c=fgetc(in);
if( c == '{')
{

fprintf(out,"%c%s",'{',"blockquote_begin");

}
else if (c == '}')
{

fprintf(out,"%s,%c","blockquote_end",'}');

}
else if (c != EOF)
{

fputc(c,out);

}

}while (c!=EOF);
fclose(in);
fclose(out);
free(fout);

}