system() changes char* argument address in a function in C

Question

I have function, say:

int foo(char* a)
{
    printf("%d\n", (int)a);
    char cmd[] = "echo hello";
    system(cmd);
    printf("%d\n", (int)a);
}

in C code, and then I run it on linux; after doing so, I see that printf outputs are:

274351760
1853775725

I just confused so much! Any idea?! :|

Answer 1

Works here:

---

#include <stdio.h>
#include <stdlib.h>

int foo(char* a)
{
    printf("%p\n", a);
    char cmd[] = "echo hello";
    system(cmd);
    printf("%p\n", a);
        return 0;
}

int main(void)
{
foo("OMG");
return 0;
}

---

Output:

---

$ ./a.out
0x400718
hello
0x400718