#include <stdio.h>

int main()

{
FILE *fp;                     /* The file handle for input data */
fp=stdin;
int ch;                       /* Each character read. */
int checksum = 0;             /* The checksum mod 2^16. */
int count=0;
 
printf("this will calc a simple checksum of the enered text\nPress Left Control + D to signify end of file \n",checksum,count);
while ((ch = getc(fp)) != EOF) {
        checksum = (checksum >> 1) + ((checksum & 1) << 15);
	    checksum +=(int) ch;
	        checksum &= 0xffff;       /* Keep it within bounds. */
		count++;
}
printf("checksum : 0x%08X for %i bytes\n",checksum,count);
}