Looping and strcpy

Question

#include <iostream>
#include <string>

using namespace std;

int main()
{
    int n;

    cout << "Enter n: ";
    cin >> n;
    cout << "Enter " << n << "names";

    for(int i=0; i<n; i++)
    {





    system("pause>0");
    return 0;
}

This is my unfinished code. I'm required to enter a number then it will ask me to enter n names. and after entering the names the program should sort the names alphabetically. How will I do that in Looping? I'm very confused in the looping part. Yeah, I know what I will code when I'm finished in looping. I'm just confused and having problems in this part. Thanks in Advance!

try a array of `strings` to store the value of names. Then in the end(outside the loop) call a sort routine. — Aman Deep Gautam, Oct 23 '13 at 01:24
See I would not do sorting while I am getting data as if you try to do that complexity will be `O(n^2)`. Rather get all the required string and then call a custom qsort. Note that you may have to write and the comparator function shall be overloaded for comparison of strings to include the unequal length case. I hope you understand the point. — Aman Deep Gautam, Oct 23 '13 at 06:32

score 1 · Accepted Answer · edited May 23 '17 at 12:10

Here's an STL version of what you're trying to do:

#include <iostream>
#include <vector>
#include <cstdlib>
#include <string>
#include <algorithm>

int main() {
    std::vector<std::string> names;

    int num = 0;
    std::cout << "Please enter a number: ";
    std::cin >> num;
    std::cout << "\n";

    std::string name;

    for (int i = 0; i < num; ++i) {
        std::cout << "Please enter name(" << (i+1) << "): ";
        std::cin >> name;
        names.push_back(name);
    }

    //sort the vector:
    std::sort(names.begin(), names.end());

    std::cout << "The sorted names are: \n";

    for (int i=0; i<num; ++i) {
        std::cout << names[i] << "\n";
    }

    return 0;
}

However, this version is a case-sensitive sort, so whether or not that performs to your requirements could be problematic. So, a possible next step to get closer to case-insensitive sorting is to use this bit of code before the vector is sorted:

    //transform the vector of strings into lowercase for case-insensitive comparison
    for (std::vector<std::string>::iterator it=names.begin(); it != names.end(); ++it) {
        name = *it;
        std::transform(name.begin(), name.end(), name.begin(), ::tolower);
        *it = name;
    }

The only caveat with this method is that all your string will be converted to lowercase, though.

REFERENCES:

https://stackoverflow.com/a/688068/866930

How to convert std::string to lower case?

@greatwolf: my original intention was not to do the entire thing, but I was quite engrossed with the problem and ended up doing the above, and at that point I thought that I should at least share my efforts. So, in some way my doing it in its entirety was a happy accident. Thanks for you feedback, though. :) — jrd1, Oct 23 '13 at 08:15

Looping and strcpy

1 Answers1