Weighted GPA Calculator

#include <stdio.h>
#include <stdlib.h>

int main()
{
    char grade;
    float gradeScore;
    int numberClasses;
    int n;
    float score;
    float GPA;
    n=0;
    gradeScore=0;
    numberClasses=0;
    printf("How many classes are you taking?\n");
    scanf("%d",&numberClasses);
    printf("Please enter your letter grade in a class:\n");
    printf("If the class is a weighted class, input one letter grade higher, \n");
    printf("if you also have an 'a' in that class, type 'h' for your weighted GPA.\n");
        scanf("%s",&grade);
            if(grade=='h'){
            gradeScore=5.0;
            }else if(grade=='a'){
            gradeScore=4.0;
            }else if(grade=='b'){
            gradeScore=3.0;
            }else if(grade=='c'){
            gradeScore=2.0;
            }else if(grade=='d'){
            gradeScore=1.0;
            }else{
            gradeScore=0.0;
            }
            score=score+gradeScore;
            n=n+1;
    while(n<(numberClasses)){
        printf("Please enter your letter grade in an other class:\n");
        scanf("%s",&grade);
        if(grade=='h'){
            gradeScore=5.0;
        }else if(grade=='a'){
            gradeScore=4.0;
        }else if(grade=='b'){
            gradeScore=3.0;
        }else if(grade=='c'){
            gradeScore=2.0;
        }else if(grade=='d'){
            gradeScore=1.0;
        }else{
            gradeScore=0.0;
        }
        score=score+gradeScore;
        n=n+1;
    }
    GPA=score/(float)numberClasses;
    printf("Your GPA is: %.2f",GPA);

    return 0;
}