Look at the output of this link(scroll down to see the output) to find out what I'm trying to accomplish
The problem is with the for loop on line number 9-11
for(i=0; i<=0.9; i+=0.1){
printf("%6.1f ",i);
}
I expected this to print values from 0.0 until 0.9 but it stops after printing 0.8, any idea why ??
Using float here is source of problem. Instead, do it with an int:
int i;
for(i = 0; i <= 10; i++)
printf("%6.1f ", (float)(i / 10.0));
Output:
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
Ideally floating point should not be used for iteration, but if you want to know why change your code and see how.
for(float i=0; i<=0.9f; ){
i+=0.1f;
System.out.println(i);
}
Here is the result.
0.1
0.2
0.3
0.4
0.5
0.6
0.70000005
0.8000001
0.9000001
your 9th value exceeds 0.9.
0.9 in C also exceed 0.9 by the same amount?
Floating point arithmetic is inexact in computing. This is because of the way that a computer represents floating point values. Here's an excerpt from an MSDN article on the subject:
Every decimal integer can be exactly represented by a binary integer; however, this is not >true for fractional numbers. In fact, every number that is irrational in base 10 will also be >irrational in any system with a base smaller than 10.
For binary, in particular, only fractional numbers that can be represented in the form p/q, >where q is an integer power of 2, can be expressed exactly, with a finite number of bits.
Even common decimal fractions, such as decimal 0.0001, cannot be represented exactly in >binary. (0.0001 is a repeating binary fraction with a period of 104 bits!)
Link to the full article: https://support.microsoft.com/kb/42980
Floating point number cannot precisely represent decimals, so rounding errors accumulate:
#include <iostream>
#include <iomanip>
using namespace std;
int main() {
float literal = 0.9;
float sum = 0;
for(int i = 0; i < 9; i++)
sum += 0.1;
cout << setprecision(10) << literal << ", " << sum << endl;
return 0;
}
Output:
0.8999999762, 0.9000000954
You loop is right, but the float comparison in loops is not safe. The problem is that a binary floating point number cannot exactly represent 0.1
This would work.
for(i=0.0; i<=0.9001; i+=0.1){
printf("%6.1f ",i);
