随机文件生成器循环不能生成正确数量的文件

我使用ofstream生成随机文件，其中存储有文本。然而，似乎应该指定生成多少.txt文件的fileNum变量不起作用。生成的.txt文件数量与实际指定的数量有较大差异。有时是4(或3或2)，有时是正确的。我不太确定哪里不对，我对c++很陌生

string genRandStr(int len, int seed) {
    // Add a seed, so a different random number is generated each time
    srand(time(seed));
    char alphaNum[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
    int strlen = sizeof(alphaNum) - 1;
    string randStr = "";
    for (int i = 0; i < len; i++) {
        randStr += alphaNum[rand() % strlen];
    }
    return randStr;
}
//main function
int main()
{
    int fileNum;
    cout << "FILEWARS - SAFE VERSION - USE WITH CARE" << endl;
    cout << "Made By: David Yue" << endl;
    cout << "Enter the amount of files you wish to create: ";
    cin >> fileNum;
    if (cin.fail()) {
        cout << "Value must be an integer." << endl;
    }
    if (fileNum >= 30) {
        cout << "SAFE VERSION RESTRICTION: File Amount may not exceed 30" << endl;
        main();
    } else {
        ofstream file1;
        stringstream fileName;
        for (int i = 0; i <= fileNum; i++) {
            fileName << genRandStr(6, time(i) ) << ".txt";
            file1.open(fileName.str());;
            for (int i = 0; i < 10; i++) {
                file1 << genRandStr(100, time(i)) << "n";
            }
            file1.close();
            file1.clear();
            fileName.str("");
            fileName.clear();
            Sleep(1000);
        }
        system("pause");
    }
}