Question

float a = 0.7;
if(a<0.7)
  printf("true");
else
  printf("false");

OUTPUT : true

Now , if I change the value of a to say 1.7 ,then

float a = 1.7;
if(a<1.7)
  printf("true");
else
  printf("false");

OUTPUT : false

Since 0.7 is treated as a double (HIGH PRECISION) and a is a float (LESS PRECISION) , therefore a < 0.7 , and in second case it should be the same again , so it should also print true. Why the difference in output here ?

PS : I have already seen this link.

Answer 1

If float and double are IEEE-754 32 bit and 64 bit floating point formats respectively, then the closest float to exactly 1.7 is ~1.7000000477, and the closest double is ~1.6999999999999999556. In this case the closest float just happens to be numerically greater than the closest double.