Question

#include <stdio.h>
int main(void) {
float funds = 1.0, cost = 0.1;
int candies = 0;
while(cost <= funds) {
candies += 1;
funds -= cost;
cost += 0.1;
}
printf("%d candies with $%.2f left over.\n",candies,funds);
return 0;
}

When you compile and run this code you get 3 candies with $0.40 left over.

Without knowing how floating point numbers work in a computer, would this result be expected? Explain why or why not. Explain why this result, in fact, occurred.

Answer 1

In the computer system, the floating-point number is represented by using IEEE floating-point representation.

The float data type in Programming Language C is stored in the computer system by using IEEE single-precision floating-point representation as given below:

In single precision representation, 1 bit is used as a sign bit, 8 bits are used for the exponent, and 23 bits are used for the mantissa, and X-127 code is used.

The sign bit is stored in a single bit.

0 -> Positive

1 -> Negative

Yes the given output is expected by the given source code.

The statement by statement explanation of the given source code is given below:

#include <stdio.h>

int main(void)
{
//float type variable declaration and initialization
float funds = 1.0, cost = 0.1;
  
//integer type variable declaration and initialization
int candies = 0;
  
//while loop
while(cost <= funds)
{
//increment the candies by one
candies += 1;
  
//decrement the funds by cost value
funds -= cost;
  
//increment the cost by 0.1
cost += 0.1;
}
  
//display the value of candies and funds on the computer screen
printf("%d candies with $%.2f left over.\n",candies,funds);
return 0;
}

OUTPUT:

3 candies with $0.40 left over.

The while() loop will execute for three times.

The value of all three variable in each of the iteration will be:

Iteration 1:

candies = 1
funds = 0.90
cost = 0.20

Iteration 2:
candies = 2
funds = 0.70
cost = 0.30

Iteration 3:
candies = 3
funds = 0.40
cost = 0.40