C++文件操作无法写入的问题

using namespace std;

int main(){/*fstream file1;ofstream file2;file1.open("A.dat", ios::in);file2.open("abc.dat", ios::trunc);double temp,data[1600];int index = 0;for(int i=0;i//file1 >> temp;//data[i] = temp;file2 //if (i % 40 == 0)file2 index++;}*/ofstream file3;file3.open("b.txt", ios::trunc);for (int j = 0; j file3 file3 }file3.close();cout int abc;cin >> abc;}