What is the logic behind this? Tell me

Question

Give a solution to this question. I thing that the correct answer is the "right" but the actual answer is not the same. Anybody explain me how it is....
#include <stdio.h>
int main()
{
float f1=0.1;
if(f1==0.1)
printf("Equal");
else
printf("not equal");
}

Answer 1

0.1 is double. 0.1f is float.

Comparing float to double might get unexpected result, like in your code f1==0.1 returns false. Compare float to float. f1==0.1f returns true.

Answer 2

f1 is float
0.1 is double

float 0.1 representation: 3d cc cc cd (32 bits ieee754)
double 0.1 representation: 3f b9 99 99 99 99 99 9a (64 bits ieee754)

They're not equal....!!