Thread: Strings are not concatenating according to my understanding.

So the point of this code, was to take a number and then that number will mean you are allowed to concatenate a number of string so to the original string.

It worked!!

But, not as well as I'd hoped.

There is a TEENY tiny bug in this code, for example if i type the number five and for my strings I type the strings "The Friends of Ringo Ishikawa"

I get TheFriendsOfRingoIshikawa as intended, but before that comes these this weird character and an a. So, if I type in the number 5 when prompted and then The Friends of Ringo Ishikawa I get the output: ö aTheFriendsOfRingoIshikawaIshikawa

What happened?

Code:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdarg.h>


char*variable_string(int num, char*a, ...);


int main()
{


  int num = 0;
  char*string = (char*)malloc(sizeof(char)*100);
  string[100] = '\0';
  printf("Please enter the number of strings you want to add to the string.");
  scanf("%d", &num);
  printf("\n num is %d", num);
  printf("\nNow please enter the strings you wish to involve in your char");
  for(int i = num; i > 0; i--)
  {
    printf("\nnum is %d", i);
    //fgets(string, sizeof((char*)string), stdin);
    scanf("%s", string);
    /*printf("\n%s", string);*/
    variable_string(num, string);
  }


  //variable_string(num, string);
  printf("\nand the string is %s", variable_string(num, string));
  return 0;
}


char*variable_string(int num, char*x,...)
{
  va_list arg_ptr;
  char*a = (char*)x;
  va_start(arg_ptr, x);
  char*b = va_arg(arg_ptr,char*);
  strcat((char*)b, (char*)a);


  va_end(arg_ptr);


  //printf("%s", (char*)b);
  return (char*)b;
}

In main, you need two strings: one string to store ths overall result and one string to store the string read from the user.

Note that you aren't actually making use of varargs in this way: you should ditch both the loop and user input and manually test with something like variable_string(2, result_string, "hello", "world"). Otherwise, you're just writing a complicated wrapper for strcat that ultimately merely calls strcat.