HackerRank C- Students Marks Sum

Complete the function, marks_summation(int* marks, char gender, int number_of_students) which returns the total sum of:

marks of boys if gender=b
marks of girls if gender=g
The programs reads the elements of marks along with gender . Then, it calls the function marks_summation(marks, gender, number_of_students) to get the sum of alternate elements as explained above and then prints the sum.

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
int marks_summation(int* marks, int number_of_students, char gender) {
     int s = 0, i = 0;
    if (gender == 'g') {
        i++;
    }
    for (; i < number_of_students; i = i+2) {
        s += marks[i];       
    }
    return s;
}

int main() {
    int number_of_students;
    char gender;
    int sum;
  
    scanf("%d", &number_of_students);
    int *marks = (int *) malloc(number_of_students * sizeof (int));
 
    for (int student = 0; student < number_of_students; student++) {
        scanf("%d", (marks + student));
    }
    
    scanf(" %c", &gender);
    sum = marks_summation(marks, number_of_students, gender);
    printf("%d", sum);
    free(marks);
 
    return 0;
}