So I'm new to programming, I learned a bit of C and figured I would write a program that calculates grade letters from percents. I'm not sure What I did wrong. I'm sure you guys can figure this out pretty easily, I'ts probably something simple and dumb I'm missing. It says the problem occurs on line 15. I would appreciate if someone could help me figure out what I am doing wrong. Open to any feedback too, thank you.

```
int main() {

   char grade[] = {
     'A',
     'A-',
     'B+',
     'B',
     'B-',
     'C+',
     'C',
     'C-',
     'D+',
     'D',
     'D-',
     'F'
   };
   double percent;

   char result;

   printf("Enter Grade Percentage: ");
   scanf("%f", & percent);

   if (percent >= 93) {
     result = grade[0];
   } else if (percent = 90, 91, 92) {
     result = grade[1];
   } else(percent = 87, 88, 89) {
     result = grade[2];
   } else(percent = 83, 84, 85, 86) {
     result = grade[3];
   } else(percent = 80, 81, 82) {
     result = grade[4];
   } else(percent = 77, 78, 79) {
     result = grade[5];
   } else(percent = 73, 74, 75, 76) {
     result = grade[6];
   } else(percent = 70, 71, 72) {
     result = grade[7];
   } else(percent = 67, 68, 69) {
     result = grade[8];
   } else(percent = 63, 64, 65, 66) {
     result = grade[9];
   } else(percent = 60, 61, 62) {
     result = grade[10];
   } else(percent < 60) {
     result = grade[11];
   }
   printf("Grade %s", result);
   return 0;
 }

```