我想问一下这C语言递归2个f(k-1)什么意思，哪一步执行到哪一步？

#include
void f(int k)
{char a[26]={'A','B','C','D','E','F','G','H', 'I','J','K','L','M','N','O','P', 'Q','R','S','T','U','V','W','X','Y','Z'};
if(k>=1)
{ f(k-1);
printf("%c",a[k-1]);
f(k-1);
}
}
int main()
{

int n;
scanf("%d",&n);
f(n);
}

看这样排版的代码真是痛心，试问你能看得下去？