Students Marks Sum HackerRank Solution
You are given an array of integers, marks, denoting the marks scored by students in a class.
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The alternating elements marks0, marks2, marks4 and so on denote the marks of boys.
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Similarly,marks1, marks3, marks5 and so on denote the marks of girls.
The array name, marks, works as a pointer which stores the base address of that array. In other words, marks contains the address where marks0 is stored in the memory.
For example, let marks = [3,2,5] and marks stores 0x7fff9575c05f. Then, 0x7fff9575c05f is the memory address of marks0.
Function Description
Complete the function, marks_summation in the editor below.
marks_summation has the following parameters:
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int marks[number_of_students]: the marks for each student
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int number_of_students: the size of marks[]
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char gender: either 'g' or 'b'
Returns
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int: the sum of marks for boys if gender = b, or of marks of girls if gender = g.
Input Format
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The first line contains number_of_students, denoting the number of students in the class, hence the number of elements in marks.
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Each of the number_of_students subsequent lines contains marks(i).
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The next line contains gender.
Constraints
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1 <= number_of_students <= 10^3
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1 <= marks(i) <= 10^3 (where 0 <= i < number_of_students)
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gender = g or b
Sample Input 0
3
3
2
5
b
Sample Output 0
8
Explanation 0
marks = [3, 2, 5] and gender = b.
So, marks0 + marks2 = 3 + 5 = 8.
Sample Input 1
5
1
2
3
4
5
g
Sample Output 1
6
Explanation 1
marks = [1, 2, 3, 4, 5] and gender = g
So, sum = marks1 + marks3 = 2 + 5 = 8.
Sample Input 2
1
5
g
Sample Output 2
0
Explanation 2
marks = [5] and gender = g
Here, marks(1) does not exist. So, sum = 0.
Solution
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
//Complete the following function.
int marks_summation(int* marks, int number_of_students, char gender) {
//Write your code here.
int sum = 0;
for(int i = (gender == 'b' ? 0 : gender == 'g' ? 1 : -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;
}
Steps used in solving the problem -
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First we have imported required header files.
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Then, we created marks_summation() function. uses a for loop to iterate over the array of marks and add up the marks of either all the boys or all the girls, based on the gender character passed in as an argument.
