C Basic Week 1 (Tao cau)

#include<stdio.h>
# include <stdlib.h>
# include <time.h>
typedef struct string
{
char tu[10];
} string;

int ngaunhien(int n)
{
int myNum , yourNum;
myNum = rand () % n;
return myNum;
}

void nhap(string A[], int n)
{
int i, a;
for(i=0;i<n;i++)
{
a=i+1;
printf("Xin moi ban nhap tu thu %d: ", a);
gets(A[i].tu);
}
}
void main()
{
int a, b, c , d, a1, a2, a3, a4, a5, a6, i;
srand ((unsigned)time(NULL));
printf("Ban muon nhap bao nhieu article: ");
scanf("%d", &a);
printf("Ban muon nhap bao nhieu noun: ");
scanf("%d", &b);
printf("Ban muon nhap bao nhieu verb: ");
scanf("%d", &c);
printf("Ban muon nhap bao nhieu preposition: ");
scanf("%d", &d);
string article[a], noun[b], verb[c], preposition[d];
printf("Xin moi ban nhap article!\n");
getchar();
nhap(article, a);
printf("Xin moi ban nhap noun!\n");
nhap(noun, b);
printf("Xin moi ban nhap verb!\n");
nhap(verb, c);
printf("Xin moi ban nhap preposition!\n");
nhap(preposition, d);
for(i=0;i<10;i++)
{
a1=ngaunhien(a);
a2=ngaunhien(b);
a3=ngaunhien(c);
a4=ngaunhien(d);
a5=ngaunhien(a);
a6=ngaunhien(b);
printf("%s %s %s %s %s %s\n", article[a1].tu, noun[a2].tu, verb[a3].tu, preposition[a4].tu, article[a5].tu, noun[a6].tu);
}
}