clearing a char array c

Question

I thought by setting the first element to a null would clear the entire contents of a char array.

char my_custom_data[40] = "Hello!";
my_custom_data[0] = '\0';

However, this only sets the first element to null.

or

my_custom_data[0] = 0; 

rather than use memset, I thought the 2 examples above should clear all the data.

Answer 1

Why not use memset()? That's how to do it.

Setting the first element leaves the rest of the memory untouched, but str functions will treat the data as empty.

Answer 2

void clearArray (char *input[]){
    *input = ' '; 
}

Answer 3

Pls find below where I have explained with data in the array after case 1 & case 2.

char sc_ArrData[ 100 ];
strcpy(sc_ArrData,"Hai" );

Case 1:

sc_ArrData[0] = '\0';

Result:

-   "sc_ArrData"
[0] 0 ''
[1] 97 'a'
[2] 105 'i'
[3] 0 ''

Case 2:

memset(&sc_ArrData[0], 0, sizeof(sc_ArrData));

Result:

-   "sc_ArrData"
[0] 0 ''
[1] 0 ''
[2] 0 ''
[3] 0 ''

Though setting first argument to NULL will do the trick, using memset is advisable

Answer 4

You should use memset. Setting just the first element won't work, you need to set all elements - if not, how could you set only the first element to 0?