MIért nem fordul le a program?

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

typedef struct IZE{

char betu;

struct IZE * NEXT;

} ELEM;

void PUSH(char c, ELEM **H){

ELEM *tmp;

tmp=(ELEM*)malloc(sizeof(ELEM));

if (tmp!=NULL){

(*tmp).betu=c;

(*tmp).NEXT=*H;

(*H)=tmp;

}

}

char POP(ELEM **H){

char c;

if ((*H)!=NULL){c=(**H).betu;

(*H)=(**H).NEXT;}

return c;

}

int main(){

int i;

ELEM *H=NULL;

char c;

for(i=0;i<5;i++){

scanf("%c ",&c);

PUSH(c,&H);

}

for(i=0;i<5;i++)

printf("%c",POP(&H));

}