#34713: C++輸出科學記號用：cout << scientific << setprecision(2) << ans << endl;
double ans;
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C++輸出科學記號用：
cout << scientific << setprecision(2) << ans << endl;
double ans;
.....................
C++輸出科學記號用：
cout << scientific << setprecision(2) << ans << endl;