How to create a progress bar in C++

[RezaAb]

Hello guys,

I have finished a code including a for loop with thousands of times calculations and I want to create a progress bar for the counter. I tried several codes which could be found on the web but most of them were problematic.
I appreciate it if you guys offer me a code maybe an inline method to create this.

Best,

[jonnin]

if you know the total number of iterations, it should just be % based. If in a gui, with a progress bar widget, its literally progbar.setposition(percentage done) or very nearly this in .net/MFC.

if doing it by hand, you can just write the % out every so often.

[dhayden]

Here's how I did it with text recently. The code processes a large collection of files and prints "10% 20% 30% ... 100%".

TargetPct is the next percentage mark that it will print. targetCount is the value of i that represents that target percentage. Since I'm going through a vector, the targetCount is one less than you might expect: e.g., if there are 100 items, then targetCount will be 9, 19, 29, ... 99 rather than 1, 10, 20, ..., 100. If I used the latter then it would never print 100% because the loop exits at 99 instead of 100.

The size of the array isn't going to be huge so I don't have to worry about overflow when computing targetCount

    int targetPct = 10;
    int targetCount = files.size() * targetPct / 100; - 1;
    if (files.empty() || !hdl)
	rc = -1;

    for (size_t i=0; rc == 0 && i<files.size(); ++i) {
	if (i == targetCount) {
	    cerr << targetPct << "% ";
	    targetPct += 10;
	    targetCount = files.size() * targetPct / 100 - 1;
	}
	...
    }

[RezaAb]

Thank you guys for the answers.
dhayden, I tried to run the code in a very simple example like the following code:

#include <iostream>
#include <cmath>
#include <vector>

using namespace std;


int main() {
	int barWidth = 1;
	vector<int> counter(7040);

	for (int j = 0; j < 7040; j++) {
		counter[j] = j;

		// creating a wait bar for the calculations! 

		int targetPct = 10;
		int targetCount = counter.size() * targetPct / 100; -1;
		if (counter.empty() || !hdl)
			rc = -1;

		for (size_t i = 0; rc == 0 && i<counter.size(); ++i) {
		if (i == targetCount) {
				cerr << targetPct << "% ";
				targetPct += 10;
				targetCount = counter.size() * targetPct / 100 - 1;
		}
	}

But the "rc" and "hd1" are unknown in the code. Could you please explain this issue.
Thanks.

[dhayden]

That was basically a cut/paste from some code I have. Here is a working program.

#include <iostream>
#include <cmath>
#include <vector>

using namespace std;

int
main()
{
    unsigned limit = 40000000;

    // creating a wait bar for the calculations! 
    int targetPct = 10;
    unsigned targetCount = limit * targetPct / 100 - 1;

    for (size_t j = 0; j < limit; j++) {
	if (j == targetCount) {
	    cerr << targetPct << "% ";
	    targetPct += 10;
	    targetCount = limit * targetPct / 100 - 1;
	}
    }
}