Question

I have this code for returning percentage of grades less than 60. But it doesn’t result in the desired percent. Someone help me figure out what’s wrong.

public float getPercentFailing(float[] grades) {

    float sum= 0;

    for (int i = 0; i < .6; i++) {
        sum = sum + grades[i];
        return sum/100;
    }
    return 0;
}

Answer 1

Try something like this. You need to first add all of the grades up, which is what you’re doing in the for loop. Now since we only want the grades over 60 we use an if statement to check if the value is above 60. If it is, add it to the sum and tally one to int count to keep track of how many grades we’ve added so far.

for (int i = 0; i < grades.length; i++) {      //loop through all the grades
   if(grade[i] < 60) {                         //if the grade is over 60
       sum = sum + grades[i];                  //add the grade to the sum
       count++                                 //remember how many grades so we can get average
   }
}

Then divide the sum of the grades by the total number of grades, or grades.length and return it.

return sum/count ;                             //calculate average

Everything together now:

public float getPercentFailing(float[] grades) {
    int count=0;
    float sum= 0;
    for (int i = 0; i < grades.length; i++) {
          if(grade[i] < 60) {
             sum = sum + grades[i];
             count++
          }
    }
    return sum/count;

}