怎么用ofstream输出固定长度的字符数组？

#include<iostream>
#include<fstream>
#include <cstring>
using namespace std;
int main(){
    char a[14] ="haha";
    cout<<"char[14]:  "<<sizeof(a)<<"  "<<strlen(a)<<endl;
    ofstream fout;
    fout.open("disk.txt");
    fout<<a;
    fout << "\n";
    fout.close();
    return 0;
} 

我想输出14个字符到文本里去，而不是只有4个，请问怎么实现

#include<iostream>
#include<fstream>
#include <cstring>
void padright(char * s, int n, char c)
{
int b = 0;
for (int i = 0; i < n; i++)
{
if (!b && s[i] == '\0') b = 1;
if (b) s[i] = c;
}
s[n] = '\n';
}
int main(){
    char a[15] ="haha"; //因为\0也需要一个字节，所以是15
    cout<<"char[14]:  "<<sizeof(a)<<"  "<<strlen(a)<<endl;
    ofstream fout;
    fout.open("disk.txt");
    padright(a, 14, ' '); //结尾用空格填充
    fout<<a;
    fout << "\n";
    fout.close();
    return 0;
}