Confused about expression evaluation

[R3.RyozKidz]

i havent learn boolean now~ T_T..
i wan to buy a book and learn now..~.. blek..`

[dcs]

Short-circuit evaluation - Wikipedia, the free encyclopedia
Lazy evaluation - Wikipedia, the free encyclopedia

[n00bcoder]

another one of my n00b questions : { I have this book which I'm trying to do exercises from and some of the questions I have no clue about!}

flota a = 0.7;
if(a < 0.7)
  printf("A");
else
  printf("B");

The book says the o.p is A. Can someone please explain why that's the o.p? I'm completely confused

[dcs]

Loss of precision and data types.

#include<stdio.h>

int main()
{
   float a = 0.7;
   /*
    * The value 0.7 a double; when 'a' is initialized, it loses precision when
    * being stored as a float. This is done silently.
    * 
    * In the comparison below, the float value 'a' is compared to the double
    * value 0.7. In the process 'a' is promoted to a double, but it doesn't gain
    * back any precision already lost in the initialization.
    */
   if ( a < 0.7 )
   {
      puts("A"); /* the answer I get */
   }
   else
   {
      puts("B");
   }
   /*
    * If we make the comparison of 'a' with the float value 0.7, both will have
    * lost the same amount of precision and the expected answer is what we get.
    */
   if ( a < 0.7F )
   {
      puts("C");
   }
   else
   {
      puts("D"); /* the answer I get */
   }
   return 0;
}

/* my output
A
D
*/

[n00bcoder]

thanks a lot

btw, is there any specific "must read" book/website where a lot of such things are very clearly mentioned or taken up as examples etc. so that I don't have to come across such problems only in tests?

BTW, I'm currently referring to Kernighan&Ritchie.

[R3.RyozKidz]

if i wan to know more about thing kind of stuff , wat kind of reference u guys suggest? any suggestion ?

[WingedPanther]

K&R is a good resource. The ANSI standard is another (not user-friendly) option.

[n00bcoder]

char p[] = "%d\n";
p[1] = 'c';
printf(p,65);

The program prints A

can someone please explain the logic in this one?

[WingedPanther]

65 is the ascii code for A.

[n00bcoder]

please take time to explain the logic of the program. I just can't seem to figure it out myself

char *x = "Alice";  // this means that x is a char pointer which points to the starting location of string "Alice"
n = strlen(x); 
*x = x[n]; // but what is this? x was a pointer so what does this statement mean? 
for(i = 0; i<=n;i++)
{
  printf("%s", x);
  x++;
}