C++ 重载 cout 输出 __int64

最新推荐文章于 2025-02-15 19:08:10 发布

原创最新推荐文章于 2025-02-15 19:08:10 发布 · 669 阅读

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e.g.

#include <iostream>

using std::cout;

std::ostream & operator<<(std::ostream &os, unsigned __int64 inum)
{
	char sznum[27] = {0};// maximum 18,446,744,073,709,551,616
	sprintf(sznum,"%I64u",inum);// original number.
	int ilen = strlen(sznum);
	int i = ilen % 3 -1;
	if(i < 0)
		i = 3 -1;
	int j = 0;
	int k = 0;
	for(j = 0;j<ilen;j++)
	{
		if(i<0 && k>0)
		{
			cout<<',';// show separator character.
			k++;
			i = 3 -1;
		}
		cout<<(char)sznum[j];// show it.
		k++;
		i--;
	}
	return os;
}

#include <iostream>
#include <fstream>

using namespace std;

class cc
{
public:
    cc(const char *pout_file, unsigned __int64 i);
private:
    friend std::ostream & operator << (std::ostream &os, unsigned __int64 i);
};

cc::cc(const char *pout_file, unsigned __int64 i)
{
    std::ofstream fout;
    fout.open(pout_file,std::ios_base::in|std::ios_base::out|std::ios_base::trunc);
    fout<<i<<endl;
    fout.close();
}

std::ostream & operator << (std::ostream &os, unsigned __int64 i)
{
    char szstr[21] = {0};
    sprintf(szstr,"%I64u",i);
    return os << szstr;
}

int main()
{
    cc cc("test.txt",12345678901234567890);
    return 0;
}