Question

I need to write a program where it takes 2 integers from a file. Then it has to make a pyramid from those 2 numbers. It has to look like this:

I’ve wrote the code and it works as I want to, bet I can’t think of a way how make it look a pyramid like.

Here’s how it looks when I do it:

And this is my code:

#include <fstream>
using namespace std;

    int main(){

        ifstream inFile("Duomenys.txt");
        ofstream outFile("Rezultatai.txt");
        int N,M,smth,suma=0;

        inFile >> N >> M;
        smth=N;

        while(N<=M){
            for(int i=smth;i<=N;i++){
                outFile<<i<<" ";
                suma+=i;
                if(i==N){
                    for(int i=N-1;i>=smth;i--){
                        outFile<<i<<" ";
                        suma+=i;
                    }
                }
            }
            outFile<<endl;
            N++;
        }
        outFile<<endl<<"Skaiciu suma: "<<suma;

        inFile.close();
        outFile.close();
        return 0;
    }

So my question would be, how to make it that my answer would be shaped in pyramid like in example?

Answer 1

#include <fstream>
#include <iostream>
#include <iomanip>
#include <assert.h>

using namespace std;

template <class T>
int numDigits(T number)
{
    int digits = 0;
    while (number) {
        number /= 10;
        digits++;
    }
    return digits;
}

int main()
{
    ifstream inFile("Duomenys.txt");
    ofstream outFile("Rezultatai.txt");
    int N,M,smth,suma=0;

    inFile >> N >> M;
    smth=N;

    // assuming positive numbers
    assert(N>=0 && M>=0);
    // this will be the size of each printed number
    int nd = numDigits<int>(M)+1;

    while(N<=M){
        for(int i=N;i<=M;i++)
            outFile << setw(nd) << " ";
        for(int i=smth;i<=N;i++){
            outFile << setw(nd) << i;
            suma+=i;
            if(i==N){
                for(int i=N-1;i>=smth;i--){
                    outFile << setw(nd) << i;
                    suma+=i;
                }
            }
        }
        outFile<<endl;
        N++;
    }
    outFile<<endl<<"Skaiciu suma: "<<suma;

    inFile.close();
    outFile.close();
    return 0;
}