Hacker-rank problem -marks sum problem of students. ( C language )

//Hackerrank problem -marks sum problem of students.

#include <stdio.h>

#include <string.h>

#include <math.h>

#include <stdlib.h>

int marks_summation(int* marks , int number_of_students , char gender)

{

    int sum = 0 , i;

    if ( gender == 'b' )

    {

        for ( int i = 0; i < number_of_students; i += 2 )

        {

            sum += marks[i];

        }

    }

    else

    {

        for ( int i = 1; i < number_of_students; i += 2 )

        {

            sum += marks[i];

        }

    }

    return sum;

}

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;

}