C Programming Code Examples
C > Data Structures Code Examples
Queue implementation using single linkedlist
/* Queue implementation using single linkedlist */
#include<stdio.h>
#include<stdlib.h>
struct node
{
int n;
struct node* next;
};
typedef struct node sn;
sn *qit(sn *);
sn *rit(sn *);
sn *q =NULL;
static int k=1;
int main()
{
char i;
sn *qp;
do
{
printf("
Press 1 to put an element in queue
");
printf("Press 2 to remove an element from queue
");
printf("Press any other to exit
");
printf("
Enter choice:");
scanf("%d",&i);
switch(i)
{
case 1:
if(k==1)
{
k=0;
qp=malloc(sizeof(sn));
q=qp;
printf("Enter element:");
scanf("%d",&qp->n);
qp->next = NULL;
break;
}
else
{
q = qit(q);
break;
}
case 2:
if(k==1)
{
printf ("Queue list Empty
");
break;
}
else
{
q = rit(qp);
qp=q;
break;
}
default:
break;
}
}
while (i==1 || i==2);
return 0;
}
sn *qit(sn *p)
{
sn *t;
t=malloc(sizeof(sn*));
printf("Enter element:");
scanf("%d",&t->n);
p->next = t;
t->next = NULL;
return t;
}
sn *rit(sn *sq)
{
sn *st;
st=sq;
printf("
Removed element is: %d",sq->n);
if(sq->next == NULL)
{
printf("
Last element
");
k=1;
return NULL;
}
else
{
sq = sq->next;
free(st);
return sq;
}
}
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