array searching vs nested if else in c++ -

what array searching version of loop? same loop below without nested if else.

test t; int a; int b; int c; int d; int f;  for(int = 0; < gradecount;i++){     if(t.getscore() <= 100 && t.getscore() >= 90)         a++;     else if(t.getscore() >= 80 && t.getscore() <= 89)         b++;     else if(t.getscore() >= 70 && t.getscore() < 79)         c++;     else if(t.getscore() >= 60 && t.getscore() < 69)         d++;     else if(t.getscore() <= 59)         f++; } 

this program self-explaining. hope helps.

#include <iostream> #include <string> using namespace std;   int main()  {    int rank[5]={0};    //rank[0] grade f   //rank[1] grade d   //rank[2] grade c   //rank[3] grade b   //rank[4] grade    int num=0;   cout<< "enter number b/w 0-100, press -1 exit"<<endl;    while(num != -1)   {      cin>>num;      int onetenthofnum = num/10;      int index = (onetenthofnum<=5)? 0: onetenthofnum%5;      rank[index]++;    }    return 0; }