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Is there a function for string rotate ?

"This is a string. "

Rotate to :
"his is a string. T"

Rotate to :
"is is a string. Th"

....

I use it for LCD Display for Scroll.

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0 erik malund over 21 years ago

I use it for LCD Display for Scroll.
The easy, effective way to scroll is to add dispaly length of the message at the end of the message. Then all you need is to bump the start.

Erik
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0 erik malund over 21 years ago

I use it for LCD Display for Scroll.
The easy, effective way to scroll is to add dispaly length of the message at the end of the message. Then all you need is to bump the start.

Erik
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0 Drew Davis over 21 years ago in reply to erik malund

Off the top of my head:

char* strrol (char* src)
    {
    char* d = src;
    char* s = d + 1;
    char c = *d;

    while (*s++)
        {
        *d++ = *s;
        }

    *d++ = c;
    *d = 0;
    } // strrol

That will cost you a lot of time, though, copying the string over and over. You could simply have back-to-back copies of the string. Or, change your transmit routine to use a modular offset and send the string in two pieces:

void send (char* s, int offset)
    {
    int l = strlen(s);
    int i;

    for (i = offset; i < l; ++i)
        {
        OutputToLcd (s[i]);
        }
    for (i = 0; i < offset; ++i)
        {
        OutputToLcd (s[i]);
        }

    }

Lots of ways to get this result, with different speed/space tradeoffs.