How to group an array of variables based on flags assigned to them with minimal code in C# -

i have array has 4 elements example :

int[] = new int[5]; 

the value : a[0] = 10,a[1]=5,a[2]=15,a[3]=10,a[4]=0;

i have flag ,

public bool[] flag = new bool[4]{false,false,false,false}; 

based on need assign above values variable named b[5].

if flag false,it add existing values of b ,

else reset values of a b.

i have tried following code seems lengthy

count[0]=20,count[1]=20;count[2]=20;count[3]=20; flag[0]=true,flag[1]=true,flag[2]=true,flag[3]=false;  void display(int[] count,int[]flag) {              if (flag[0] == true)     {         resetcount[0] = count[0];     }     if(flag[1]==true)     {         resetcount[1] = count[1];     }     if (flag[2] == true)     {         resetcount[2] = count[2];     }     if(flag[3]==true)     {         resetcount[3] = count[3];     }     if (flag[0] == false)     {         resetcount[0] += count[0];     }     if (flag[1] == false)     {         resetcount[1] += count[1];     }     if (flag[2] == false)     {         resetcount[2] += count[2];     }     if (flag[3] == false)     {         resetcount[3] += count[3];     } } 

here resetcount[0]=10,resetcount[1]=10,resetcount[2]=10,resetcount[3]=10;

if flag false count value added , if true count value set reset count above 0,1,2

count[0]=20,count[1]=20;count[2]=20;count[3]=20; flag[0]=true,flag[1]=true,flag[2]=true,flag[3]=false; resetcount[0]=10,resetcount[1]=10,resetcount[2]=10,resetcount[3]=10; 

so resetcount :

resetcount[0]=20,resetcount[1]=20,resetcount[2]=20,resetcount[3]=30; 

like loop?

count[0]=20,count[1]=20;count[2]=20;count[3]=20; flag[0]=true,flag[1]=true,flag[2]=true,flag[3]=false;  void display(int[] count,int[]flag) {            (int = 0 ; i<=3 ; i++)   {     if (flag[i])     {       resetcount[i] = count[i];     }     else     {       resetcount[i] += count[i];     } 

}