error ..simple array

[gNash]

main()
{
char arr[20]="hai";

strcat(arr,arr);

printf("%s",arr);
}

its printed haihai..

when i replace hai to haii..

i got segmentation fault..

Why?...

 

[Flash Gordon]

gNash wrote, On 23/04/07 12:33:

main()
{
char arr[20]="hai";

strcat(arr,arr);

printf("%s",arr);
}

its printed haihai..

when i replace hai to haii..

i got segmentation fault..

Why?...

Blind luck. Passing overlapping strings to strcat invokes undefined
behaviour, which means that as far as the C language is concerned
ANYTHING is allowed to happen. You happen to have had the most common
results with your two tries, but just as well have caused your computer
to show hard porn whenever your mother or partner looks at it.