void evalpo(stack *s)
{
printf("\n Enter the postfix expression : ");
scanf(" %s",a);
int len=strlen(a);
printf("\n Length of above expression is : %d \n",len);
for(i=0; i<len ; i++)
{
if(check(a[i])==0) //meaning its an operand
{
pushe(s,a[i]-48);
}
if(check(a[i])==1) //meaning its an operator
{
printf("\n Popping the top two \n");
p1=pope(s);
p2=pope(s);
p0=op(p2,p1,a[i]); //top ke neeche waala ka operation with top
pushe(s,p0);
}
}
printf("\n Evaluating postfix exp = %d \n",s->st[s->top]);
options(s);
}
void
main(int argc, char *argv[])
{
int i;
node_t * head = NULL; node_t * heao = NULL;
head = malloc(sizeof(node_t)); heao = malloc(sizeof(node_t));
head->val = 0; heao->val = 9;
head->next=NULL; heao->next=NULL;
head->id=0; heao->id=0;
for(i=1; i<
//PAL_SIZE
7
; i++)
{
if(!(i%3)) printf("\n ");
printf("%d,", i);
pushe(head, i);
}
printf("\n");
for(i=8; i>0; i--)
{
if(!(i%3)) printf("\n ");
printf("%d,", i);
pushe(heao, i);
}
print_list(head);
printf("\n");
print_list(heao);
free(head);
free(heao);
}
void evalpre(stack *s)
{
printf("\n Enter the prefix expression : ");
scanf(" %s",a);
int len=strlen(a);
printf("\n Length of above expression is : %d \n",len);
for(i=len-1; i>=0 ; i--)
{
if(check(a[i])==0) //meaning its an operand
{
pushe(s,a[i]-48);
}
if(check(a[i])==1) //meaning its an operator
{
printf("\n Popping the top two \n");
p1=pope(s);
p2=pope(s);
p0=op(p1,p2,a[i]); //top ka top ke neeche waale se operation
pushe(s,p0);
}
}
printf("\n Evaluating prefix exp = %d \n",s->st[s->top]);
options(s);
}
void main()
{
char c;
char a[30];
do
{
clrscr();
printf("1.ENTER 1 TO PUSH ELEMENT TO THE STACK\n");
printf("2.ENTER 2 TO POP THE ELEMENT FROM THE STACK\n");
printf("3.ENTER 3 TO DISPLAY THE ELEMENTS OF THE STACK\n");
printf("4.enter 4 to add element at the end\n");
printf("5.enter 5 to enter element after specified position/n");
printf("enter your choice : ");
scanf("%c",&c);
switch(c)
{
case '1':printf("enter the element to be pushed ");
fflush(stdin);
gets(a);
push(a);
break;
case '2':pop();getch();break;
case '3':dis();getch();break;
case '4':printf("enter the element to be pushed ");
fflush(stdin);
gets(a);
pushe(a);
break;
}
}while(c!='0');
}