Fill char array with input and I dont understand the output - c

Question

So I'm learning the char arrays in C. I wrote a little program which works with functions and reads input from terminal and on EOF will printf the char array.
If I enter, for example: hello my name is and press enter, I receive this output: hello my z Ͳ
I don't understand where the z Ͳ comes from. Can someone explain it to me?
#include <stdio.h>
const int MAXLENGTH = 10;
int getLine(char[], int);
int main(void) {
char inputString[MAXLENGTH];
getLine(inputString, MAXLENGTH);
printf("%s", inputString);
return 0;
}
// Functions:
int getLine(char destArray[], int length) {
int returnLength;
int input;
for (int i = 0; i < length - 1; i++) {
if ((input = getchar()) != EOF) {
destArray[i] = input;
returnLength = i;
}
}
return returnLength;
}

Answer 1

There are multiple problems in your code:
you do not store a null terminator at the end of the destination array in getLine().
you should stop read from stdin when you get a newline ('\n') or an EOF value.
Here is a modified version:
#include <stdio.h>
const int MAXLENGTH = 10;
int getLine(char[], int);
int main(void) {
char inputString[MAXLENGTH];
getLine(inputString, MAXLENGTH);
printf("%s\n", inputString);
return 0;
}
// Functions:
int getLine(char destArray[], int length) {
int i, c;
for (i = 0; i < length - 1; i++) {
c = getchar();
if (c == EOF || c == '\n')
break;
destArray[i] = c;
}
destArray[i] = '\0';
return i;
}
Running this program will show that hello my name is does not fit in the destination array as the program's output will be hello my
In your program, you were not storing anything beyond the end of the buffer, because you correctly test i < length - 1, but printf did read beyond the 9-th byte set by getLine() and printed whatever contents was in memory at those addresses until it finds a null byte, which is undefined behavior. The weird output is a benign side effect of undefined behavior, the program could have crashed too. The bytes in the memory probably correspond to values stored in the stack for the main() function local frame and return address. Different compilers, different platforms or even different invocations of the same program could produce different output (the latter may seem unlikely, but would happen on OS/X because of stack randomisation).