1 #include<stdlib.h>
 2 #include<stdio.h>
 3 #include<time.h>
 4 int main()
 5 {
 6     int a[15];
 7     int i,j;
 8     srand(time(0));　//seed
 9     for (i=1;i<=15;i++)
10         a[i]=rand()%100+1;  //范围
11     for (i=1;i<=3;i++)
12     {
13         for(j=(i-1)*5+1;j<=(i-1)*5+5;j++)
14             printf("%-3d ",a[j]);
15         printf("\n");
16     }
17     return 0;
18 }

 1 #include<stdlib.h>
 2 #include<stdio.h>
 3 #include<time.h>
 4 int main()
 5 {
 6     int a[15];
 7     int i,j;
 8     srand(time(0));
 9     for (i=1;i<=15;i++)
10         a[i]=rand()%100+1;
11     for (i=1;i<=15;i++)
12     {
13         printf("%-3d ",a[i]);
14         if (i%5==0) printf("\n");
15     }
16     return 0;
17 }

25  90  83  76  23  
39  83  98  7   58  
65  51  67  18  99