Mega Code Archive
Queue in C
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#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#define MAX 100
char *p[MAX], *pop(void);
int spos = 0;
int rpos = 0;
void add(void), push(char *q), print(void), remove(void);
void add(void)
{
char s[256], *p;
do {
printf("spos %d: ", spos+1);
gets(s);
if(*s==0) {
break;
}
p = (char *) malloc(strlen(s)+1);
if(!p) {
printf("Out of memory.\n");
return;
}
strcpy(p, s);
if(*s) {
push(p);
}
} while(*s);
}
void print(void)
{
int t;
for(t=rpos; t < spos; ++t)
printf("%d. %s\n", t+1, p[t]);
}
void remove(void)
{
char *p;
if((p=pop())==NULL) {
return;
}
printf("%s\n", p);
}
void push(char *q)
{
if(spos==MAX) {
printf("List Full\n");
return;
}
p[spos] = q;
spos++;
}
char *pop(void)
{
if(rpos==spos) {
printf("No more.\n");
return NULL;
}
rpos++;
return p[rpos-1];
}
int main(void)
{
char s[80];
register int t;
for(t=0; t < MAX; ++t) {
p[t] = NULL;
}
while(1) {
printf("Add(A), Print(P), Remove(R), Quit(Q): ");
gets(s);
*s = toupper(*s);
switch(*s) {
case 'A':
add();
break;
case 'P':
print();
break;
case 'R':
remove();
break;
case 'Q':
exit(0);
}
}
return 0;
}
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