Convert int to char (ASCII value)

Question

I am trying to convert an int to a char using the ASCII value. The int is randomly generated between 97 and 122 (from a to z).

How can I generate a random number between 97 and 122 and convert it to a char?

I searched many answers before asking my question, but none solved the problem or was completely related to my need. Even this didn't work.

Here is what I'm trying to do: in a for loop, the program generates a random number and converts it to an int. This is converted to its ASCII value and then placed into a QString. When the for loop is finished, I send the QString to a line_edit.

By following the above link, I only got an m.

Here's my code:

QString str;
int maxlenght = 16; //the user will be able to set himself the maxlenght
for (int i =0; i<maxlenght; i++)
{
    int random = 97 + (rand() % (int)122-97+1);
    char letter = (char)random;
    if(i > 0)
    {
        str[i] = letter;
    }
}

And though the random number is generated in the loop, it always gives me the same char.

related/dupe: http://stackoverflow.com/questions/19724346/generate-random-characters-in-c — NathanOliver, Dec 20 '16 at 13:50
I searched an answer to my question before but didn't found this one. Thanks, will try it. — Newokmyne, Dec 20 '16 at 13:53
You should not tag a question both [C] and [C++]. They are different languages. — abelenky, Dec 20 '16 at 14:22
Ok i solvec one problem. But it should give me only lowercase char between a and z. so why do I get uppercase letter or '.', '^', and some other special char? — Newokmyne, Dec 20 '16 at 14:24
Yes, sorry @abelenky. Just because these are similar and my question can be solved both for C and C++. Is there a way to modify it? — Newokmyne, Dec 20 '16 at 14:28

Tu Bui · Accepted Answer · 2016-12-20T14:44:07.420

-1

You need to convert string to QString after that.

#include <iostream>
#include <cstdlib>
#include <string>
using namespace std;

int main()
{
    string str="";
    int maxlenght = 16; //the user will be able to set himself the maxlenght
    for (int i =0; i<maxlenght; i++)
    {
        int rand_num = 97 + (rand() % (122 - 97 + 1));
        char letter = static_cast<char>(rand_num);
        str += letter;
    }
    cout << str << endl;
    return 0;
}

edited Dec 20 '16 at 14:44

answered Dec 20 '16 at 14:09

Tu Bui

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What's the point of casting `(int)(122 - 97 + 1)`? (also why aren't you just using the actual result of this calculation?) – UnholySheep Dec 20 '16 at 14:11
@UnholySheep It demonstrates the range [97,122] that the random number will be generated, as requested by the OP. U can replace it by the actual value of 26 but the readers may not understand where that number comes from. – Tu Bui Dec 20 '16 at 14:15
The cast is still pointless (and not even "proper" C++, use `static_cast` instead) – UnholySheep Dec 20 '16 at 14:16
the range is between 97 and 122m so why do I get uppercase letter or '.', '^', and some other special char? – Newokmyne Dec 20 '16 at 14:24
@Newokmyne : it is because you forgot the parenthesis around (122-97+1) – Tu Bui Dec 20 '16 at 14:38
@UnholySheep: u r rite. We don't need that cast. Code updated. – Tu Bui Dec 20 '16 at 14:41
Ah yes right... Thank you ^^ (I upvoted your reply by the way) – Newokmyne Dec 20 '16 at 14:43

Convert int to char (ASCII value)

1 Answers1