本文介绍了一种使用C++标准库fstream进行文件存在性检查的方法，并演示了如何根据文件是否存在来选择读取或写入模式。
fstream fs(“fname”, ios_base::in);// attempt open for read
if (!fs)
{
// file doesn't exist; don't create a new one
}
else //ok, file exists. close and reopen in write mode
{
fs.close();
fs.open(“fname”, ios_base::out); // reopen for write
}
You can just do the opposite for ios::noreplace:
fstream fs(“fname”, ios_base::in);// attempt open for read
if (!fs)
{
// file doesn't exist; create a new one
fs.open(“fname”, ios_base::out);
}
else //ok, file exists; close and reopen in write mode
{
fs.close()
fs.open(“fname”, ios_base::out); // reopen for write
}
可以用这种方法判断文件是否存在vc++ ios::in ios::out 含义
最新推荐文章于 2025-07-13 00:53:01 发布
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