Creates 4 variables. The value of joe is 0, mary is 1, bob is 2, and fran is 3.

#include <stdio.h>
enum CONSTANT{
CAT=1, DOG, BIRD
};
char *test(int animal){
switch(animal){
case CAT:return "cat";break;
case DOG: return "dog";break;
case BIRD: return "bird";break;
default: return "unknown";break;
}
}
int main(){
printf("%s\n",test(DOG));
return 0;
}

/*phần include ở trên và code ở trên*/
/*
this is main
*/
int main(){
char **vpt=get_list_exec(0);
int r=0;
while(vpt[r]){
printf("%s ",vpt[r]);
}
}

/*find cmd in path and return malloc string */
char *which(const char *word){
char **vpath=str2arword(getenv("PATH"),':');
char buf[266],*rpt=0;
size_t r=0;
while(vpath[r]){
strcpy(buf,vpath[r]);strcat(buf,"/");
strcat(buf,word);
if(access(buf,F_OK)==0) {
rpt=(char *)malloc(strlen(buf));
if(rpt) strcpy(rpt,buf);
return rpt;
}
r++;
}
free((void *)vpath);
return NULL;
}

#include <dirent.h>
#include <string.h>
#include <unistd.h>
#include <malloc.h>
/*
cut a string by sep character,
return a pointer of array string
*/
char **str2arword(const char *str,char sep){
if(str==NULL) return NULL;
char *path=str;
size_t len=strlen(path);
size_t frag=0,r=0,count=0,msize;
char **vpath;
/*first count how many*/
while(*path) if(*path++==sep) frag++;
vpath=(char **)malloc( (frag+2)*sizeof(char*)+len+1 );
path=str;
vpath[r]=vpath+frag+2;
while(*path){
*(vpath[r]+count++)=*path++;
if(*path==sep) {
*(vpath[r]+count)=NULL;
vpath[r+1]=vpath[r]+count+1;
count=0,path++,r++;
}
}
vpath[r+1]=NULL;
return vpath;
}
/*23:00
get a list of file exec in PATH environment variable
*/
char **get_list_exec(const char *epath){
#define MAX_NUMBER_POINTER 512
char *path = epath;
char **vcpt = 0;
size_t r=0,len=0,item=0,count=1;
char **vret=(char **)malloc(sizeof(char *)*MAX_NUMBER_POINTER);
struct dirent *dent;
DIR *dirp;
if(vret==NULL) return -1;
if(epath==NULL) path = getenv("PATH");
vcpt = str2arword(path,':');
/*in this loop I got the total len of all string and number of item*/
while(vcpt[r]){
dirp= opendir(vcpt[r]);
if(dirp==NULL) goto end_loop;
while( dent=readdir(dirp) ) {
if( (strcmp(dent->d_name,".")) && strcmp(dent->d_name,"..") )
if((dent->d_type==DT_REG)||(dent->d_type==DT_LNK)){
char buf[512]; /*form a canonical name*/
strcpy(buf,vcpt[r]);strcat(buf,dent->d_name);
if(! access(buf,X_OK))
{
size_t len1 = strlen(dent->d_name);
char *get = malloc(len1+1);
if(get==NULL) return -1;
strcpy(get,dent->d_name);
vret[item]=get;
len +=len1;
item++;
}
}
if(item>=MAX_NUMBER_POINTER){
count++;
void *tmp=malloc(sizeof(char *)*MAX_NUMBER_POINTER*count);
if(tmp==NULL) return -1;
memcpy(tmp,vret,sizeof(char *)*MAX_NUMBER_POINTER*(count-1));
free(vret);
vret=(char **)tmp;
}
}
closedir(dirp);
end_loop:;
r++;
}
/*when i go here len and item are reserve for make string*/
vret[item]=0;
return vret;
}