Thread: C memory allocation ( malloc ) issue - strange characters on the console

Hi Guys,

Greetings you in the forum! I would like to use char array manipulations instead of using strcpy/strcat methods.

So I created a C function which require a char array as an input parameter and it returns with the new char array ( which contains the input parameter 3 times succesively )

After running the program I got some bizarre, strange characters on the console: The result: dogsdogsdogsh=C:zńĹKÄ☺
It is a bit disturbing for me... What do you think, which would be my problem? What is the background of the correct memory allocation ?

Any help would be appreciated! Very thx for your help!

Here is my code snippet, you can run it ( I use DevCpp ):

Code:

#include<stdio.h>
char *WriteParamStr3Times(char* paramStr); // the prototype of the function
main()
{
	// define maximum 10 long string
	char myString[10]="dogs";		
	
	// call the function which writes the parameter 3 times successively
	char *resultString = WriteParamStr3Times(myString);		
	
	// write result string
	printf("The result: %s", resultString);
}


// try to write 3times in consecutive mode
char *WriteParamStr3Times(char* paramStr)
{	
	char *lokalStr = (char *) malloc(strlen(paramStr)*3); // allocate memory 3x the parameter string
	int i, j;		
	for (i=0, j=0; i< strlen(paramStr)*3; i++, j++)				
		{
			if( j == strlen(paramStr))  // when paramStr finished, starting again
			{				
				j=0;
			}
			lokalStr[i]	= paramStr[j];	
		}			
	return lokalStr;
}