12-1.c

#include<stdio.h>
#include<stdlib.h> //standard library
int main()
{
FILE *fp;
char ch,filename[10];
printf("Please enter the file name:");
scanf("%s",filename);
if((fp=fopen(filename,"w"))==NULL)
{
printf("Unable to open this file\n");
exit(0);
}
ch=getchar();
printf("Please enter a string in the disk(Ends with a #):");
ch=getchar();
while(ch!='#')
{
fputc(ch,fp);
putchar(ch);
ch=getchar();
}
fclose(fp);
putchar(10);
return 0;
}