Consider the C program shown below.

#include < stdio.h >
#define print(x) printf("%d ", x)
int x;
void Q(int z) {
   z += x; print(z);
}
void P(int *y) {
   int x = *y+2;
   Q(x); *y = x-1;
   print(x);
}
main(void) {
   x = 5;
   P(&x);
   print(x);
}

The output of this program is

Consider the following three C functions:

[P1] int*g(void)
     {
       int x=10;
       return(&x);
     }

[P2] int*g(void)
      {
        int *px;
       *px = 10;
        return px;
      }

[P3] int*g(void)
     {
       int *px
       px =(int*)malloc (size of (int));
       *px = 10;
       return px;
     }

Which of the above three functions are likely to cause problems with pointers?