Prog#178: read from keyboard & write into file until $

/*
read from keyboard & write into file until $
Program#178
*/
#include<stdio.h>
main()
{
char c;
FILE *fp;
fp=fopen ("pr178", "w");
if(fp==NULL)
{
printf("file open error");
return 0;
}
scanf("%c", &c);
while(c='$')
{fprintf(fp, "%c", c);
scanf("%c", &c);
}
fclose (fp);
}