给一维数组赋值并按条件输出的问题

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define N 100
int main()
{
int a
;
int i,o;
srand((unsigned)time(NULL));
for(i=0;i<N;i++)
{
a[i]=rand()%N;
if(a[i]>=50)
printf("a[%d]=%d\n",i,a[i]);
}

return 0;
}