c语言中设置数组元素的个数

#include <stdio.h>

#define NUMBER 1000

int main(void)
{
    int i, j, num, a[NUMBER], b[11] = {0};
    printf("student number: ");
    do
    {
        scanf("%d", &num);
        if(num < 1 | num > 1000)
            printf("the range of number is 1-%d.\n", NUMBER);
    }
    while(num < 1 | num > 1000);
    
    printf("students score: \n");
    for(i = 0; i < num; i++)
    {
        do
        {
            printf("NO.%d = ", i + 1); scanf("%d", &a[i]);
            if(a[i] < 0 | a[i] > 100)
                puts("the range of score is 0-100.");    
        }
        while(a[i] < 0 | a[i] > 100);
        b[a[i] / 10]++;
    }
    
    printf("---distribution plot---\n");
    printf("      100: ");
    for(i = 0; i < b[10]; i++)
    {
        putchar(‘*‘);
    }
    putchar(‘\n‘);
    
    for(i = 9; i >= 0; i--)
    {
        printf("%3d - %3d: ", i * 10 , i * 10 + 9);
        for(j = 0; j < b[i]; j++)
        {
            putchar(‘*‘);
        }
        putchar(‘\n‘);
    }
    return 0;
}