Thread: The Timing is incorret

All these times should be the same:
Total Time Duration0.841 ms
Total Time Duration2.384 ms
Total Time Duration0.4 ms
Total Time Duration0.411 ms
Total Time Duration0.411 ms
Total Time Duration0.55 ms
Total Time Duration0.411 ms
Total Time Duration0.401 ms
Total Time Duration0.41 ms
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What am I doing wrong?

Code:

#include< iostream >
#include< iomanip >
#include< cstdlib >
#include< ctime >
#include< cstdio >
#include< fstream >

const int vSize = 3;
using namespace std;



int main()
{
   
    int vec[vSize]={5000, 5000, 5000};//,50000//,100000,200000,400000};

    //Declare the clock variables
    clock_t start,finish, start1, finish1, start2, finish2;
    clock_t startAll;

    //Declare and initialize all the variables
   double duration, duration1, duration2;
    
    //Declare the streams and the input and output files
    ifstream inFile;
   ofstream outFile;

    inFile.open("input1.txt");
   outFile.open("A:/output1.txt");

    
int Sum=0;
    
     
    
     for (int iterationcountselector = 0; iterationcountselector < vSize; ++iterationcountselector)
    {
         start=clock();
         for(int i =0; i < vec[iterationcountselector] ; i++)
         {
              Sum++;
              outFile<< Sum<<endl;
         }
    

     /*     finish=clock();
         duration=(double)(finish-start)/CLOCKS_PER_SEC;
         cout<<"          "<< setw(4)<< duration;*/
         
    
          finish=clock();
         duration=(double)(finish-start)/CLOCKS_PER_SEC;
         cout<<"Total Time Duration"<< duration<<" ms"<< endl;

    }
    for (iterationcountselector = 0; iterationcountselector < vSize; ++iterationcountselector)
    {
         
    start1=clock();
         for(int i =0; i < vec[iterationcountselector]; i++)
         {
              
               Sum++;
              outFile<< Sum<<endl;
         }
    

          finish1=clock();
         duration1=(double)(finish1-start1)/CLOCKS_PER_SEC;
         cout<<"Total Time Duration"<< duration1<<" ms"<< endl;
    }

for (iterationcountselector = 0; iterationcountselector < vSize; ++iterationcountselector)
    {
         
    start2=clock();
         for(int i =0; i < vec[iterationcountselector]; i++)
         {
              
               Sum++;
              outFile<< Sum<<endl;
         }
    

          finish2=clock();
         duration2=(double)(finish2-start2)/CLOCKS_PER_SEC;
         cout<<"Total Time Duration"<< duration2<<" ms"<< endl;
    }


    return 0;
}//end of main