Comparison of scanf and cin performance and comparison of scanfcin Performance

Comparison of scanf and cin performance and comparison of scanfcin Performance

My lab machine configuration is:

I connected stdin to the input file and tested the data of magnitude 104, 105, 106, and 107 in sequence. The result is as follows.

The bar chart is as follows:

 

 

The following table is displayed when the time is 1, 10000:

The time of cin/scanf is as follows:

It can be seen that the time when cin reads the same data is 3.5 ~ of scanf ~ 4 times.

The test code is as follows:

 1 #define _CRT_SECURE_NO_WARNINGS 2 #include <iostream> 3 #include <string> 4 #include <ctime> 5 #include <cstdio> 6 using namespace std; 7 const int N = 10000; // modify this to change the size of data 8 int main() 9 {10     clock_t start;11     FILE* ptr = freopen("data.out", "rb", stdin);12 13     start = clock();14     15 16     for (int cnt = 0; cnt < N; cnt++) {17             int tmp;18             // cin >> tmp;    // remove the comment symbol to test on cin19             scanf("%d", &tmp);20     }21 22     clock_t end;23     end = clock();24     25     double seconds = (double)(end - start) / CLOCKS_PER_SEC;26     27     printf("%lf\n", seconds);28 29     fclose(stdin);30     return 0;31 }

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