自定义函数之字符提取

#include<iostream>
#include<cstring>
using namespace std;
void fun(char a[],char b[])
{
    int i,j=0,l,t,k;
    l = strlen(a);
    for (i = 0; i <= l; i++)
    {
        if (a[i] == 'a' || a[i] == 'e' || a[i] == 'i' || a[i] == 'o' || a[i] == 'u')
        {
            b[j] = a[i];
            j++;
        }
    }
    b[j] = '\0';
    k = strlen(b);
    for (i = 0; i <= k-1; i++)
    {
        for (j = 0; j <= k-1; j++)
        {
            if (a[j] > a[j + 1])
            {
                t = a[j+1];
                a[j+1] = a[j];
                a[j] = t;
            }
        }
    }
}
int main()
{
    char a[100], b[100];
    gets_s(a);
    fun(a, b);
    cout << b << endl;;
    return 0;
}