Session 4 Homework - Arithmetic Operations

📚 What You'll Practice

This homework focuses on mastering arithmetic operations in C programming. You'll learn about operators, order of operations, and how to perform calculations.

Goal: Become comfortable with mathematical operations and PEMDAS order of operations!

📋 Instructions

Understand the five basic arithmetic operators (+, -, *, /, %)
Learn PEMDAS order of operations
Practice with different data types in calculations
Pay attention to integer vs float division
Experiment with parentheses to control order

🧮 Program 1: Basic Calculator

Perform all basic arithmetic operations!

What it does:

Gets two numbers from the user and performs all basic arithmetic operations (addition, subtraction, multiplication, division, modulo).

#include <stdio.h>

int main() {
    int num1, num2;
    
    printf("Enter first number: ");
    scanf("%d", &num1);
    
    printf("Enter second number: ");
    scanf("%d", &num2);
    
    printf("\n=== CALCULATION RESULTS ===\n");
    printf("%d + %d = %d\n", num1, num2, num1 + num2);
    printf("%d - %d = %d\n", num1, num2, num1 - num2);
    printf("%d * %d = %d\n", num1, num2, num1 * num2);
    printf("%d / %d = %d\n", num1, num2, num1 / num2);
    printf("%d %% %d = %d\n", num1, num2, num1 % num2);
    
    return 0;
}

🧪 Test Cases

Input: 15, 4 → 15+4=19, 15-4=11, 15*4=60, 15/4=3, 15%4=3
Input: 20, 6 → 20+6=26, 20-6=14, 20*6=120, 20/6=3, 20%6=2

📐 Program 2: PEMDAS Practice

Demonstrate order of operations!

What it does:

Shows how parentheses affect the order of operations and demonstrates PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition, Subtraction).

#include <stdio.h>

int main() {
    int a = 10, b = 5, c = 2;
    int result1, result2, result3, result4;
    
    // Different ways to calculate: a + b * c
    result1 = a + b * c;        // Multiplication first: 10 + (5 * 2) = 20
    result2 = (a + b) * c;      // Parentheses first: (10 + 5) * 2 = 30
    result3 = a * b + c;        // Multiplication first: (10 * 5) + 2 = 52
    result4 = a * (b + c);      // Parentheses first: 10 * (5 + 2) = 70
    
    printf("a = %d, b = %d, c = %d\n", a, b, c);
    printf("\n=== ORDER OF OPERATIONS ===\n");
    printf("a + b * c = %d (multiplication first)\n", result1);
    printf("(a + b) * c = %d (parentheses first)\n", result2);
    printf("a * b + c = %d (multiplication first)\n", result3);
    printf("a * (b + c) = %d (parentheses first)\n", result4);
    
    return 0;
}

🧪 Expected Output

a = 10, b = 5, c = 2
a + b * c = 20 (10 + 10)
(a + b) * c = 30 (15 * 2)
a * b + c = 52 (50 + 2)
a * (b + c) = 70 (10 * 7)

🔢 Program 3: Float Division

Work with decimal results!

What it does:

Demonstrates the difference between integer and float division, showing how to get decimal results.

#include <stdio.h>

int main() {
    int a = 15, b = 4;
    float x = 15.0, y = 4.0;
    float result1, result2;
    
    printf("=== INTEGER vs FLOAT DIVISION ===\n");
    printf("a = %d, b = %d\n", a, b);
    printf("x = %.1f, y = %.1f\n", x, y);
    
    printf("\nInteger division: %d / %d = %d\n", a, b, a / b);
    printf("Float division: %.1f / %.1f = %.2f\n", x, y, x / y);
    
    // Mixed operations
    result1 = a / y;  // int / float = float
    result2 = x / b;  // float / int = float
    
    printf("\nMixed operations:\n");
    printf("%d / %.1f = %.2f\n", a, y, result1);
    printf("%.1f / %d = %.2f\n", x, b, result2);
    
    return 0;
}

🧪 Expected Output

Integer division: 15 / 4 = 3 (truncated)
Float division: 15.0 / 4.0 = 3.75 (exact)
Mixed: 15 / 4.0 = 3.75, 15.0 / 4 = 3.75

🔢 Program 4: Modulo Operations

Master the modulo operator!

What it does:

Demonstrates various uses of the modulo operator (%) for finding remainders and checking divisibility.

#include <stdio.h>

int main() {
    int num;
    
    printf("Enter a number: ");
    scanf("%d", &num);
    
    printf("\n=== MODULO OPERATIONS ===\n");
    printf("Number: %d\n", num);
    printf("%d %% 2 = %d (remainder when divided by 2)\n", num, num % 2);
    printf("%d %% 3 = %d (remainder when divided by 3)\n", num, num % 3);
    printf("%d %% 5 = %d (remainder when divided by 5)\n", num, num % 5);
    printf("%d %% 10 = %d (remainder when divided by 10)\n", num, num % 10);
    
    printf("\n=== DIVISIBILITY CHECKS ===\n");
    if (num % 2 == 0) {
        printf("%d is divisible by 2 (even number)\n", num);
    } else {
        printf("%d is not divisible by 2 (odd number)\n", num);
    }
    
    if (num % 3 == 0) {
        printf("%d is divisible by 3\n", num);
    } else {
        printf("%d is not divisible by 3\n", num);
    }
    
    return 0;
}

🧪 Test Cases

Input: 12 → 12%2=0 (even), 12%3=0 (divisible by 3), 12%5=2, 12%10=2
Input: 17 → 17%2=1 (odd), 17%3=2 (not divisible by 3), 17%5=2, 17%10=7

🧮 Program 5: Complex Expression Calculator

Calculate complex mathematical expressions!

What it does:

Calculates complex mathematical expressions using multiple operations and demonstrates the importance of parentheses.

#include <stdio.h>

int main() {
    int a, b, c;
    int result1, result2, result3, result4;
    
    printf("Enter three numbers: ");
    scanf("%d %d %d", &a, &b, &c);
    
    printf("\n=== COMPLEX EXPRESSIONS ===\n");
    printf("a = %d, b = %d, c = %d\n", a, b, c);
    
    // Different complex expressions
    result1 = a + b * c;                    // a + (b * c)
    result2 = (a + b) * c;                  // (a + b) * c
    result3 = a * b + c * a;                // (a * b) + (c * a)
    result4 = (a + b) * (c - a);            // (a + b) * (c - a)
    
    printf("\nExpression Results:\n");
    printf("a + b * c = %d\n", result1);
    printf("(a + b) * c = %d\n", result2);
    printf("a * b + c * a = %d\n", result3);
    printf("(a + b) * (c - a) = %d\n", result4);
    
    // Show step-by-step calculation for one expression
    printf("\n=== STEP-BY-STEP: (a + b) * (c - a) ===\n");
    printf("Step 1: (a + b) = (%d + %d) = %d\n", a, b, a + b);
    printf("Step 2: (c - a) = (%d - %d) = %d\n", c, a, c - a);
    printf("Step 3: %d * %d = %d\n", a + b, c - a, (a + b) * (c - a));
    
    return 0;
}

🧪 Test Cases

Input: 5, 3, 8 → Various complex calculations
Input: 10, 4, 6 → Various complex calculations

🏠 Session 4 Homework

Arithmetic Operations

📚 What You'll Practice

📋 Instructions

🧮 Program 1: Basic Calculator

What it does:

🧪 Test Cases

📐 Program 2: PEMDAS Practice

What it does:

🧪 Expected Output

🔢 Program 3: Float Division

What it does:

🧪 Expected Output

🔢 Program 4: Modulo Operations

What it does:

🧪 Test Cases

🧮 Program 5: Complex Expression Calculator

What it does:

🧪 Test Cases

🎯 Remember