Add 1 char to char[2]

Projects Programming
1

how to add a single char to char array
char array[2]={};
how to add single char to it in next line array=array+thing; doesnt work :grinning: :smiley: :grinning:

2

You could use strcat or strncat.

char a[4] = "ab";
char b[2] = "c";
strcat(a, b);
Serial.println(a);
3

also extra: is [1] is for store 2 chars (can use 0)?

4 
array[0] = 'a';
array[1] = '\0';
Serial.println(array);
5

it resets arduino

tftchar(key,colortext);
strcat(code, key);

6

A string is terminated by a zero, so for a string of length n, you need an array of size n + 1. In the example of post #2, the array a is of size 4 to contain the characters a, b, c and \0.

The code string is probably not large enough. It needs to hold both its original content and the content of key plus the zero terminating character.

7

Please show all code

8

consider code below i just posted to append chars to a char array using an index, "idx", which is reset after processing the array contents (this was done on a laptop)

#include <stdio.h>
#include <string.h>

const int CodeLen = 20;
char code [CodeLen];
int  idx = 0;

void
loop (void)
{
    char key = getchar ();

    if (key)  {
        code [idx++] = key;
        if (CodeLen == idx || '#' == key)  {
            code [idx-1] = '\0';          // overwrite '#' w/ NUL
            idx        = 0;
            if (!strcmp ("AC", code))
                printf (" AC found\n");
            else
                printf (" unknown\n");
        }
    }
}

int
main ()
{
    while (1)
        loop ();
    return 0;
}
9

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