counting number of integers in sequence

If I have an algebraic expression that makes a sequance of numbers how do I count the number of integers in the sequence and output this?

The integers are coming from a do-while loop and I don't know how to count them.

just create another variable that starts at zero and increment it with each iteration of the loop:

Code:

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#include <iostream>

int main()
{
        int iter=0;

        do{
                iter++;
                std::cout<<iter<<std::endl;
        }while(true);

        return 0;
}

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