Generate a random string in C

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Hi, in this code I'm generate random number in specific range, but I want the out put of array must be

l101
l101
l102
l104

I mean adding the word "host" to every number that is generate randomly, how can do this please??
I'm sorry about my bad english

What I have tried:

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


 <pre>
    int main (int argc, char *argv[])
    {

      char buffer[16];
      srand(time(NULL));
      int n = rand() % (8 + 1 - 4) + 4 ;
      for(int i=0;i<n;i++){
         
         int r = rand() % (104 + 1 - 101) + 101 ;

          sprintf( buffer, "host%d", r );
          printf( "No. of random selected node = %s\n", buffer[i]);
      }
  }

Posted 19-Dec-17 4:21am

Lilyanaa

Updated 19-Dec-17 5:40am

v4

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Comments

jeron1 19-Dec-17 10:26am

printf( "No. of random selected node = host%d\n", a[i]); // <== add the word 'host' here

Lilyanaa 19-Dec-17 10:31am

No, I want array must have "host101"...

jeron1 19-Dec-17 10:35am

You want an array of strings?

Lilyanaa 19-Dec-17 10:41am

yes, but how can fix this word "host" and make the number generate randomly??

2 solutions

Solution 1

Quote:
No, I want array must have "host101"...

Your array can't hold values like "host101" - it can only hold integers.
In order to get it to hold strings, you need to change it to an array that holds char pointers:

C#

char* a[50];

And then use malloc[^] to allocate space for each string inside your loop:

C#

char *str;
...
str = (char *) malloc(10);

You can then use sprintf[^] to print your "host" and the number into each string and then put it into your array.

Posted 19-Dec-17 4:50am

OriginalGriff

Comments

Lilyanaa 19-Dec-17 11:15am

Can you see my update please ?

OriginalGriff 19-Dec-17 11:26am

And?

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Rick York · Accepted Answer · 2017-12-19T04:50:00

Solution 2

Assuming you have a random room number generated, you can make the string like this :

C++

char buffer[16];
sprintf( buffer, "host%d", roomNumber );

To generate the random room number I would use this :

C++

int GetRandomValue( int minval, int maxval )
{
   int span = maxval - minval;
   int rval = rand() % span;
   int result = rval + minval;
   return result;
}

If you want rooms to range from 101 to 110 then pass those two values to the function :

C++

int room = GetRandomValue( 101, 110 );

Posted 19-Dec-17 4:50am

Rick York

Updated 19-Dec-17 4:52am

v2

Comments

Lilyanaa 19-Dec-17 11:17am

Can you see my update please ?

Rick York 19-Dec-17 11:30am

You are close. To display the buffer as a string you need to pass it to printf. As it is, you passed one character in the array to it - buffer[1]. It needs to be :

  printf( "No. of random selected node = %s\n", buffer );

If you want, you can generate a bunch of numbers and store them all in an array of integers and then you can print them all later using the same format and printf statement. That's up to you.

Lilyanaa 19-Dec-17 11:38am

oh yes thanks a lot

Rick York 21-Dec-17 18:28pm

Why did you unaccept the answer?

Lilyanaa 23-Dec-17 7:27am

Oh ,I'm so sorry inadvertent error