I want to directly calculate the minimum value of the `float` type, and here is my algorithm(Suppose that the encoding of floating-point number confirms to the IEEE 754 standard):

```
#include <math.h>
#include <limits.h>
#include <float.h>
#include <stdio.h>

float float_min()
{
    int exp_bit = CHAR_BIT * sizeof(float) - FLT_MANT_DIG;
    float exp = 2 - pow(2, exp_bit - 1);

    float m = pow(2, -(FLT_MANT_DIG - 1));

    return m * pow(2, exp);
}

int main()
{
    printf("%g\n", float_min());
}

```

The output is `1.4013e-45`. However, I find the the value of `FLT_MIN` in the `C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\include\float.h` is `1.175494351e-38F`. Who is wrong?