Creating a loop that requires input's first letter to be upper and others to be lower

Question

I have to create a loop that requires from the user to enter the first number in upper and others in lower, if the requirements are not met, the user must input once again, until the first letter is upper and others are lower.

var novaDrzava = new Država();
Console.Write("Vnesite ime (prva začetnica naj bo velika, ostale male): ");

novaDrzava.Ime = Console.ReadLine();

var drzava = novaDrzava.Ime;
var inicialka = drzava.Substring(0);
var ostale = drzava.Substring(1, drzava.Length - 1);

for (int i = 0; i <= malecrke.Length; i++) {
    if (inicialka.Contains(velikecrke[i])) {
        if (ostale.Contains(malecrke[i])) {
            break;
        } else {
            Console.WriteLine("Ponovno vnesite ime");
            novaDrzava.Ime = Console.ReadLine();
        }
    }
}

What is different here from your previous question? https://stackoverflow.com/questions/55416779/input-must-be-upper-casefirst-letter-and-lower-case-others — Steve, Mar 29 '19 at 14:21
In general it's best practice to write code in English so other people get a better feel of what you're trying to accomplish. — Jordec, Mar 29 '19 at 14:25
Possible duplicate of [Input must be upper case(first letter) and lower case (others)](https://stackoverflow.com/questions/55416779/input-must-be-upper-casefirst-letter-and-lower-case-others) — Chris Dunaway, Mar 29 '19 at 16:50

Dmitry Bychenko · Answer 1 · 2019-03-29T14:46:44.430

Keep looping until novaDrzava.Ime is valid:

  using System.Text.RegularExpressions;

  ...

  Console.Write("Vnesite ime (prva začetnica naj bo velika, ostale male): ");

  // Keep looping
  while (true) {
    // Get a new user input
    //   .Normalize() - let diacritics be represent in a standard way
    //   .Trim()      - let be nice and remove leading/trailinf white spaces 
    novaDrzava.Ime = Console.ReadLine().Normalize().Trim();

    // If input is valid one (uppercase followed zero or more lowercase) 
    // we can stop looping 
    if (Regex.IsMatch(novaDrzava.Ime, @"^\p{Lu}\p{Ll}*$")
      break;

    // input is not valid: let user know it and keep asking
    Console.WriteLine("Ponovno vnesite ime");
  }

  // From now on novaDrzava.Ime contains a valid name

Amélie Dupré · Answer 2 · 2019-03-30T15:32:20.640

Why not accept their input and format it the way you need? This would remove the need for the loop. Something like:

var teststring = ToUpperFirst("touppercase");

private string ToUpperFirst(string text)
 {
     return CultureInfo.CurrentCulture.TextInfo.ToTitleCase(text.ToLower());

     //alternatively, you could use:
     //return $"{char.ToUpper(text[0])}{(text.Length > 1 ? text.Substring(1).ToLower() : string.Empty)}";
 }

score -3 · Answer 3 · edited Apr 01 '19 at 07:25

A simple getline like there are in C & C++ should be enough, just use ifs inside to check data he already put in, and new data if they meet requirements go.

Else, if he put a bad data at a key moment ask him again and reset data he already put in.

This is a sample working in C so you should be able to replicate it in C# with a bit of rework, for one character input at one time.

#include <stdio.h>
#include <stdlib.h>

int is_upper(char *str)
{
    int idx = 0;

  if (str[idx] >= 'a' && str[idx] <= 'z') {
    return (0);
  }
  if (str[idx] >= 'A' && str[idx] <= 'Z') {
    return (1);
  }
  return (2);
}

int main(void)
{
  FILE *fp;
  char *line = NULL;
  size_t len = 0;
  ssize_t read;

  int mystrlen = 0;
  char finalstring[2048]; //to ease the algorithm so there is no need to do a dynamic allocation due to C behavior

  while ((read = getline(&line, &len, stdin)) != -1) {
    if (strlen(line) == 2) { // because \n == 1 char
        if (mystrlen == 0 && line[0] >= 'A' && line[0] <= 'Z') {
            strcat(finalstring, line);
            mystrlen++; //first letter = UPPER CASE
        }
        else if (is_upper(line) == 2 || is_upper(line) == 1 || mystrlen == 0) { //if first letter is good & we aren't at first letter, or simply bad char input
            mystrlen = 0;
            finalstring[0] = '\0';
            printf("reset\n");
        }
        else if (is_upper(line) == 0) { //when all is good
            strcat(finalstring, line);
            printf("\n%s\n", finalstring);
        }
    }
    else {
        mystrlen = 0;
        finalstring[0] = '\0';
        printf("reset\n");
        }
    }
}

Apart from this your answer is pretty vague, so its unlikely of any use to anyone. — MakePeaceGreatAgain, Mar 29 '19 at 14:23

Creating a loop that requires input's first letter to be upper and others to be lower

3 Answers3