Write a program in C for grade calculation using if…else if ladder and switch Statement. Accept marks of 3 subjects calculate total and based on it calculate Grade.

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Start

Input marks for 3 subjects (sub1, sub2, sub3)

Calculate Total Marks (total = sub1 + sub2 + sub3)

Calculate Average Marks (average = total / 3)

Check if all subjects have marks >= 33 (to pass)

• If YES, proceed to calculate the grade.
• If NO, print "FAILED" and stop.

Check the grade based on the average using if-else conditions:

• If average >= 80, assign grade 'A'.
• Else if average >= 65, assign grade 'B'.
• Else if average >= 45, assign grade 'C'.
• Else if average >= 33, assign grade 'D'.
• Else assign grade 'F' (failed).

Display total marks, average, and grade.

End


#include <stdio.h>

int main() {
    int sub1, sub2, sub3, total;
    float average;
    char grade;
    
    // Input marks for 3 subjects
    printf("Enter marks of 1st Subject: ");
    scanf("%d", &sub1);
    
    printf("\nEnter marks of 2nd Subject: ");
    scanf("%d", &sub2);
    
    printf("\nEnter marks of 3rd Subject: ");
    scanf("%d", &sub3);
    
    // Total Marks and Average
    total = sub1 + sub2 + sub3;
    average = total / 3.0;
    
    // Check if passed
    if (sub1 >= 33 && sub2 >= 33 && sub3 >= 33) {
        printf("\nTotal Marks: %d", total);
        printf("\nAverage Marks: %.2f", average);
        
        // Grade calculation using if...else if ladder
        if (average >= 80) {
            grade = 'A';
        } else if (average >= 65) {
            grade = 'B';
        } else if (average >= 45) {
            grade = 'C';
        } else if (average >= 33) {
            grade = 'D';
        } else {
            grade = 'F'; // F for fail if below 33
        }
        
        // Display grade using switch statement
        switch(grade) {
            case 'A':
                printf("\nStudent has A grade.");
                break;
            case 'B':
                printf("\nStudent has B grade.");
                break;
            case 'C':
                printf("\nStudent has C grade.");
                break;
            case 'D':
                printf("\nStudent has D grade.");
                break;
            case 'F':
                printf("\nStudent has FAILED, advised to re-take exam.");
                break;
            default:
                printf("\nInvalid grade.");
        }
    } else {
        printf("\nStudent has FAILED, advised to re-take exam.");
    }

    return 0;
}

To check whether the triangle is isosceles, scalene or equilateral triangle. in C language

 Mistakes:- 
1. Difference b/w || and &&

|| (Logical OR)

• ||(OR) operator checks whether one of condition is true or not..
• It returns:
  • True (1): If either or both conditions are true.
  • False (0): If both conditions are false.

&& (Logical AND)

• &&(AND) operator  Checks whether both conditions are true or not.
• It returns:
• True (1): If both conditions are true.
• False (0): If either one or both conditions are false.

// Check if the triangle is equilateral , Isoceles, scalene.

#include <stdio.h>

int main() {

    int a,b,c;

    

    

    printf("Enter a side of Triangle: ");

    scanf("%d", &a);

    

     printf("Enter b side of Triangle: ");

    scanf("%d", &b);

    

     printf("Enter c side of Triangle: ");

    scanf("%d", &c);

    

    // || is OR operator it checks whether one of the condition is true or not

    // && is AND operator it checks whether both conditions are true or not.

    

    

    if(a==b && b==c){

    printf("Triangle is Equilateral"); 

    } else if(a==b || b==c || a==c) {

        printf("Triangle is Isoceles");

        } else {

            printf("Triangle is Scalene.");

    }

    return 0;

}

Calculate Compound interest in C Language

#include<stdio.h>
#include<math.h>

int main() {
float CompoundInterest, rate, time, principal, n, amount;

/*

1. Take Input from User
principal amount, rate(%), n(per yr), time(in yrs)

n = no. of times interest compounded per year

*/

rate = rate /100;

amount = principal * pow((1+r/n), n*time);

CompoundInterest = amount-principal;

/*

2. Display the Result

printf("The Total Amount: %.2f\n", amount);

printf("The Compound Interest %.2f\n", CompoundInterest);

*/

return 0;

}

CODE TESTED and RAN!

Update:-

- Reduced complexity, confusion.
- Made it understandable & readable.

Mistakes:- 

- don't forget to put comma "," after pow here's an example:-

principal * pow(1+r/n),n*time);

Calculate Simple Interest in C language

 #include<stdio.h>

int main() {

    int principal, t, rate;

    

    printf("Enter the Principal Rate: ");

    scanf("%d", &principal);

    

    printf("Enter the Time in years: ");

    scanf("%d", &t);

    

    printf("Enter the Rate: ");

    scanf("%d", &rate);

    

    int SI = (principal*t*rate)/100;

    printf("The Simple Interest is: %d", SI);

    

    

return 0;

}

CODED and Tested

1. Write a c program to display your Name, address and city in different lines.in C Language

#include<stdio.h>

int main() {

char Name[100], Address[100], City[100];

// Input Name, Address and City...

printf("Enter your Name: ");

fgets(Name, sizeof(Name), stdin);

printf("Enter your Address: ");

fgets(Address, sizeof(Address), stdin);

printf("Enter your City: ");

fgets(City, sizeof(City), stdin);

printf("---Displaying all the information below---");

printf("\nName: %s", Name);

printf("Address: %s", Address);

printf("City: %s", City);

return 0;

}


CODE:- Tested- Works.

Write a program to print multiplication table of 10 in reversed order. in C Language

 My mistakes:-

1. couldn't figure out CONDITION. just i ( ZERO OR NONE)

// Write a program to print multiplication table of 10 in reversed order.

#include <stdio.h>

int main()

{

    int n;

    scanf("%d", &n);

    for( int i = 10; i ; i--) // for(initialize; conditon; increment or decrement)

    {

        printf("%d x %d = %d\n", n, i, n*i);

    }

   

    return 0;

}

First sum of natural numbers in C language

The actual calculation behind:-

1. while(i<=n) {

    sum = sum + i;

    i++;

}

or

2. for(i = 1; i<=n; i++) {
sum += i; // sum = sum + i;
}

advantages of for loop:-
-  more easier.
- makes code concise and more clean.

// First sum of natural numbers in C language

#include <stdio.h>

int main() {

    int n, sum = 0; /// sum = 0 stores the number in memory

    printf("Enter your first N natural number: ");

    scanf("%d", &n);

    

    // Using a loop to calculate the sum

    // for(int i = 1; i <= n; i++) {

    //     printf("%d\n", i);

    //     sum += i;

    // }

    sum = (n*(n+1))/2;

    

    printf("The first sum of %d Natural numbers are: %d\n", n, sum);

    

    

    return 0;

}

FORMULA:- 

 Check whether a number is Prime Number or not

Mistakes:- 

Theory-wise:- I didn't knew what is Prime Numbers:

**Prime Number:- Divisible by 1 and itself only.

Composite Number:- Divisible by 1 and itself as well as other numbers too.

 Table of any given number in C language

Mistakes:-

1.) I put "if" instead of "for" loop which led to a huge error in the beginning.

if loop:- 

- if (condition) { // Code to be executed if the condition is true }

**for loop:-

- for (initialization; condition; update){

}

-initializes a value once then tests the condition after each iteration, 

-stops when condition is false.

2.) after putting the loop control statement, i forgot to put {  }

// Table of any given number upto 10.

#include <stdio.h>

int main() {

    // Declare the variables num, n

   int num, n;

// User enters the value of any given number

printf("Enter the value:- ");

scanf("%d", &num);

//Shows which table is being printed

printf("\nThe table of %d", num);

for (n = 1;n <= 10; n++) // for is initialization, condition, increment

{

// Prints the table upto 10 

printf("\n%d x %d = %d", num, n, num*n);

}

    return 0;

}

Palindromic Number checker with C

 Mistakes:- 

1. 1. i forgot to put } before "else" statement.
2. Logic: Store original, then compare original == reversed.

1. Key Operations: Use % to extract digits, / to remove digits, and *10 to build reversed.
2. Important: Preserve original for comparison.

Tip:-  Always close if block with } before starting an else block.

correct:- if (condition) { /* Code */ } else { /* Code */ }

#include <stdio.h>

int main() {

    int n, original, reversed = 0, remainder;

    printf("Enter the integer: ");  // Input the integer value

    scanf("%d", &n);

    // Store the original value of n

    original = n;

    // Get the reversed value of the number

    while (n != 0) {

        remainder = n % 10;          // Get the last digit

        reversed = reversed * 10 + remainder;  // Build the reversed number

        n /= 10;                     // Remove the last digit

    }

    // Check if the original number is equal to the reversed number

    if (original == reversed) {

        printf("The number is a Palindrome.\n");

    } else {

        printf("The number is not a Palindrome.\n");

    }

    return 0;

}

C- Operator and their uses with examples

1. Unary Operator

a) num-- means decrement of 5 to 4 as an example! :)

// Online C compiler to run C program online

#include <stdio.h>

int main() {

   int num = 5;

   

   printf("The value of 5 before decrement is:- %d", num);

   printf("\nThe value of 5 using decrement is:- %d", num--);

   printf("\nThe value of 5 after decrement is:- %d", num);

   

    return 0;

}

OUTPUT:-

The value of 5 before decrement is:- 5

The value of 5 using decrement is:- 5

The value of 5 after decrement is:- 4

=== Code Execution Successful ===

b) num++ is the vice-e-versa of num--

// Online C compiler to run C program online

#include <stdio.h>

int main() {

   int num = 5;

   

   printf("The value of 5 before decrement is:- %d", num);

   printf("\nThe value of 5 using decrement is:- %d", num++);

   printf("\nThe value of 5 after decrement is:- %d", num);

   

    return 0;

}

OUTPUT :-

The value of 5 before decrement is:- 5

The value of 5 using decrement is:- 5

The value of 5 after decrement is:- 6

=== Code Execution Successful ===