写了个小程序测试了一下cout函数和printf函数的效率，看来printf函数的确效率要高不少。

1 #include 
     
       2 #include 
      
         3 using namespace std; 4  5 int main() 6 { 7     long sTime, eTime, timeForCout, timeForPrintf; 8     int a[30000]; 9 10     int i;11     for (i = 0; i < 30000; i++) {12         a[i] = i;13     }14 15     sTime = clock();16     for (i = 0; i < 30000; i++) {17         cout << a[i] << "\n";18     }19     eTime = clock();20     timeForCout = eTime - sTime;21 22     sTime = clock();23     for (i = 0; i < 30000; i++) {24         printf("%d\n", a[i]);25     }26     eTime = clock();27     timeForPrintf = eTime - sTime;28 29     cout << "cout时间：" << timeForCout << "ms" << endl;30     cout << "printf时间：" << timeForPrintf << "ms" << endl;31 32     system("pause");33     return 0;34 }