Question: What I have:

```
char cmd[50] = "some text here";
char v[] = {'a','s','d','c','b'};

```

So I want to concatenate `cmd` by adding a letter from `v`.

Obviously: 

```
strcat(cmd, v[3]);

```

doesn't work because `strcat` doesn't accept the `v[n]` parameter `n = int`.

Answer: 
Do ***not*** use this:

```
strcat(cmd,&v[3]);

```

`&v[3]` is not a pointer to a null terminated string! instead use 

```
strncat(cmd, &v[3], 1);

```
the problem is that you don't use strcat as well:

```
char *strcat (char *dest, const char *src);

```

because you do 

```
char *strcat (char *dest, char src);

```

So you must declared a char \* as your char.