Conditional statements (if, else, switch-case)

Here’s a C code example demonstrating conditional statements, including if, else, and switch-case. This example uses user input to illustrate different conditions and branches based on specific values.

#include <stdio.h>

int main() {
    int age;
    char grade;

    // Prompt user for age and grade input
    printf("Enter your age: ");
    scanf("%d", &age);

    printf("Enter your grade (A, B, C, D, or F): ");
    getchar();  // Clear the newline character left by previous input
    scanf("%c", &grade);

    // If-else conditional to check age category
    if (age < 13) { 
        printf("You are a child.\n"); 
    } else if (age >= 13 && age <= 19) {
        printf("You are a teenager.\n");
    } else {
        printf("You are an adult.\n");
    }

    // Switch-case to evaluate grade
    switch (grade) {
        case 'A':
            printf("Excellent! Keep up the great work.\n");
            break;
        case 'B':
            printf("Good job! You're doing well.\n");
            break;
        case 'C':
            printf("Not bad, but there is room for improvement.\n");
            break;
        case 'D':
            printf("You passed, but consider working harder.\n");
            break;
        case 'F':
            printf("You failed. Don't give up, keep trying!\n");
            break;
        default:
            printf("Invalid grade entered.\n");
            break;
    }

    return 0;
}

Explanation of Conditional Statements

1. if, else if, and else statements

These statements allow you to execute different code based on whether a condition is true (1) or false (0).

Syntax: The if statement checks a condition inside parentheses, and if it’s true, the block of code inside {} runs.

In this example:

• if (age < 13) { ... } checks if the user is under 13; if true, it displays “You are a child.“
• else if (age >= 13 && age <= 19) { ... } checks if the age is between 13 and 19, displaying “You are a teenager.“
• else { … } is the fallback for all other values, displaying “You are an adult.”

Logical Operators like && (AND) can combine conditions (e.g., age >= 13 && age <= 19), which must all be true for the whole expression to be true.

2. switch-case statement

The switch statement is useful for checking a variable against a set of discrete values, particularly with char or int types.

Syntax: Each case represents a possible value, followed by the code block for that value.

In this example:

• switch (grade) { ... } evaluates the grade variable:
• case 'A': executes when grade is 'A', printing a message for excellent performance.
• Each case is followed by break; to prevent “fall-through” (executing subsequent cases even when one matches).
• default: provides a fallback message for any unrecognized grade value (e.g., “Invalid grade entered”).

Summary of Conditional Statements

• if, else if, else: Used for conditions that evaluate to true or false. They allow flexibility with complex expressions and combinations.
• switch-case: Efficient when testing a single variable against several discrete values, as in the case of grade.

Together, these structures let you handle a variety of logical branching scenarios in a C program, enabling tailored responses to different input values.