录入一篇英文文章（存放在字符数组a[n]中），统计单词个数，并按照单词的长度由小到大依次输出各个单词。假定这段文章不超过80个字符，单词不超过20个。
#include<stdio.h>
#define N 80
void sort(int b[20][2],int c)   //给英文单词长度排序
{
    int i,j,k,z;
    int t[2];
    for(i = 0;i < c-1;i++)
    {
        k = i;
        for(j = i+1;j < c;j++)
        {
            if(b[k][0] > b[j][0])
                k = j;
        }
        if(k!=i)
        {
            for(z = 0;z < 2;z++)
            {
                t[z] = b[i][z];
                b[i][z] = b[k][z];
                b[k][z] = t[z];
            }
        }

    }
}
int main()
{
    int flag = 0,j = 0,z = 0,i = 0,y;
    char a[80];
    int b[20][2];
    printf("请输入英文文章:\n");
    gets(a);

    while(a[i] != '\0')                                      //
    {
        if(a[i] >= 'a' && a[i] <= 'z' || a[i] >= 'A' && a[i] <= 'Z')
            flag++;
        else
        {
            b[z++][0] = flag;                            //b[][0]为单词数
            
            flag = 0;
        }
        if(flag == 1)
        {
            j++;
            b[z++][1] = i;                               //b[][1]为单词起始位置
        }
        i++;
    }

        sort(b,j);
    for(y = 0;y < j;y++)
    {
        for(z = 0;z < b[y][0];z++)
        printf("%c",a[b[y][1]+z]);
        printf("\n");
    }
    printf("%d\n",j);

    return 0;
}