C程序在gcc和llvm编译器中的行为有所不同

Question

I wrote a program that consists of main and a function expand. The problem is that the code returns the intended result when compiled and run with Xcode (latest version) however when compiled and run with gcc compiler through terminal the code is stuck immediately after running (no warnings or errors!). This is the command I use to compile the code in the terminal:

gcc expand.c -o expand -Wall -pedantic -ansi

Below is my code. I have no idea what my problem is:

#include <stdio.h>
#define MAX_LEN 100
#define ATOI_GAP 48

void expand(char s1[], char s2[]);

int main() 
{
int i;
char s2[MAX_LEN]; /* declare the target array */
char s1[4]; /* declare the source array */
s1[0] = 'a';
s1[1] = '-';
s1[2] = 'z';
s1[3] = '\0';

for(i = 0; i < MAX_LEN; ++i) {  /* print s2 array */
    printf("%d ", s2[i]);
} 

expand(s1, s2);

for(i = 0; s2[i] != '\0'; ++i) {  /* print s2 array */
    printf("%c ", s2[i]);
}

return 0;
}

/* the function gets string s1 of format "letterX-letterY"
and fills the "-" with the consequent letters from letterX to
letterY. For example, if s1 = "a-d", then s2 will be "abcd"*/

void expand(char s1[], char s2[]) {
int start = s2[0] = s1[0]; /* the first letter of the array s2 is the same as that of the array s1 */
int stop = s1[2]; /* determine at which letter we need to stop */
int j;
printf("inside expand");

for(j = 1; j < stop - '0' - ATOI_GAP; ++j) {
    s2[j] = ++start; /* fill in the gap */
}
s2[j] = '\0'; 
printf("finished expand");

}

Answer 1

Found the issue, I was incorrectly running the output C file. I previously exported the path with all my C output files, so to call the file in question I was just typing "filename" in the terminal. However, the exported path wasn't sourced properly so I wasn't getting any result. When I run the file as "./filename" everything is working.