exact representation of floating points in c

Question

void main()
{
    float a = 0.7;

    if (a < 0.7)
        printf(\"c\");
    else
        printf(\"c++\");
} 

In the above question for 0.7, \"

Answer 1

floats will be stored as described in IEEE 754: 1 bit for sign, 8 for a biased exponent, and the rest storing the fractional part.

Think of numbers representable as floats as points on the number line, some distance apart; frequently, decimal fractions will fall in between these points, and the nearest representation will be used; this leads to the counterintuitive results you describe.

"What every computer scientist should know about floating point arithmetic" should answer all your questions in detail.