求改一下代码，当有连续的数字时只输出一个换行

#include<stdio.h>
#include<string.h>
int main()
{
    char a[100] = {'0'};
    int i, b;
    while (gets(a)!=EOF)
    {
        b = strlen(a);
        for (i = 0; i < b; i++)
        {
            if ((a[i] >= '0' && a[i] <= '9')&&(a[i+1]<'0'||a[i+1]>'9'))
            {
                a[i] = '\n';
            }
            else if ((a[i] >= '0' && a[i] <= '9') && (a[i + 1] >= '0' && a[i + 1] <= '9'))
            {
                a[i] = ' ';
            }

        }
        printf("%s", a);
    }
    return 0;
}