Question

why ch must be equal to 13???

Answer 1

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <string.h>
int main(void)
{
int i,counter=0,flag=0;
char uid[25],pwd[25],s_uid[][25]={"11user1","12user2","13user3"};
char s_pwd[][25]={"Pwd1","Pwd2","Pwd3"},ch='a';
printf("\n Enter the user id : ");
scanf("%s",uid);
printf("\n Enter the password : ");
i=0;
while(1)
{
ch=getch();
if(ch==13)
break;
else if(ch==8)
{

if(i!=0)
{
printf("\b");
printf("%c",32);
printf("\b");
i--;
pwd[i]='\0';
}
else
continue;

}
else
{
printf("*");
pwd[i]=ch;
i++;
}
}
pwd[i]='\0';


for(i=0;i<=2;i++)
{
if((stricmp(uid,s_uid[i]))==0 && (strcmp(pwd,s_pwd[i]))==0)
{
flag=1;
break;
}
}

getch();
}

Answer 2

http://www.asciitable.com/

13 is the carriage return (basically enter)

Answer 3

Carriage returns alone are mostly used in Mac GUIs. Microsoft uses carriage return and line feed. Unix (and most of OSX) uses line feeds. Line feeds are ASCII and UTF-8 10 (decimal, 0x0a hexadecimal).