Array vector has "n" elements, but lenght returns "n+1" in C

Question

Hello,

I have the following question: I have a vector and I’m sure it is passed to him only one element through the following loop:

char uid[1];
while(indice1 < indice2){
    printf("Valor de indice 1 %d, indice 2 %d\n", indice1, indice2);
    uid[indice0] = recvline[indice1];
    ++indice1; ++indice0;
}

Printing the values of the indices they are respectively 11 and 12.

However, when I concatenate this string with another one via the strcat function or return its size using (int)strlen(uid), the size is 2.

I believe that the element ' 0' should be suppressed in concatenation or element counting.

Some solution?

Thank you!