Week6: Arrays (1D Arrays) in C

Q1. Student Marks, Total, Percentage and Grade

Question:
Write a C program to read marks of 5 subjects of a student, calculate the total, percentage, and assign grade according to the following criteria:

Percentage	Grade
>= 90	A
>= 80	B
>= 70	C
>= 60	D
>= 40	E
< 40	F

Program:

#include <stdio.h>

int main() {
    int marks[5], total = 0;
    float p;
    char grade;

    for (int i = 0; i < 5; i++) {
       printf("\nEnter marks: ");
       scanf("%d", &marks[i]);
       total += marks[i];
    }

    p = total / 5.0;
    if (p >= 90) grade = 'A';
    else if (p >= 80) grade = 'B';
    else if (p >= 70) grade = 'C';
    else if (p >= 60) grade = 'D';
    else if (p >= 40) grade = 'E';
    else grade = 'F';

    printf("Total: %d\nPercentage: %.2f\nGrade: %c\n", total, p, grade);

    return 0;
}
````

---

## Q2. Check if Two Marks Lists Are Identical

**Question:**
Write a C program to read two mark lists of equal size (10 elements each) and check whether they are identical or not.

**Program:**

```c
#include <stdio.h>

int main() {
    int marks1[10], marks2[10], identical = 1;

    printf("Enter 10 marks for the first list:\n");
    for (int i = 0; i < 10; i++) {
        scanf("%d", &marks1[i]);
    }

    printf("Enter 10 marks for the second list:\n");
    for (int i = 0; i < 10; i++) {
        scanf("%d", &marks2[i]);
    }

    for (int i = 0; i < 10; i++) {
        if (marks1[i] != marks2[i]) {
            identical = 0;
            break;
        }
    }

    if (identical) {
        printf("The two marks lists are identical.\n");
    } else {
        printf("The two marks lists are not identical.\n");
    }

    return 0;
}

---

Q3. Sum of All Elements in an Array

Question: Write a C program to find the sum of all elements in an integer array.

Program:

#include <stdio.h>

int main() {
    int arr[10], sum = 0;

    printf("Enter 10 integers:\n");
    for (int i = 0; i < 10; i++) {
        scanf("%d", &arr[i]);
    }

    for (int i = 0; i < 10; i++) {
        sum += arr[i];
    }

    printf("The sum of all elements is: %d\n", sum);

    return 0;
}

---

Q4. Sum of Prime Numbers in an Array

Question: Write a C program to find all prime numbers in an array and calculate their sum.

Program:

#include <stdio.h>
#include <stdbool.h>

bool isPrime(int num) {
    if (num <= 1) return false;
    for (int i = 2; i * i <= num; i++) {
        if (num % i == 0) return false;
    }
    return true;
}

int main() {
    int n, sum = 0;

    printf("Enter the number of elements: ");
    scanf("%d", &n);

    int arr[n];
    printf("Enter %d numbers:\n", n);
    for (int i = 0; i < n; i++) {
        scanf("%d", &arr[i]);
    }

    for (int i = 0; i < n; i++) {
        if (isPrime(arr[i])) {
            sum += arr[i];
        }
    }

    printf("Sum of prime numbers: %d\n", sum);

    return 0;
}

Comments