Conditional Statements

#include <stdio.h>

int main() {
    // if / else if / else
    int score = 85;
    char grade;

    if (score >= 90) {
        grade = 'A';
    } else if (score >= 80) {
        grade = 'B';
    } else if (score >= 70) {
        grade = 'C';
    } else if (score >= 60) {
        grade = 'D';
    } else {
        grade = 'F';
    }
    printf("Score: %d, Grade: %c\n", score, grade);

    // switch statement (integer/char values only)
    char command;
    printf("Enter command (q/h/r): ");
    scanf(" %c", &command);

    switch (command) {
        case 'q':
            printf("Quitting...\n");
            break;  // Without break, falls through to next case!
        case 'h':
            printf("Help menu\n");
            break;
        case 'r':
            printf("Running...\n");
            break;
        default:
            printf("Unknown command: %c\n", command);
    }

    // Fall-through (intentional)
    int day = 3;
    switch (day) {
        case 1: case 2: case 3: case 4: case 5:
            printf("Weekday\n");
            break;
        case 6: case 7:
            printf("Weekend\n");
            break;
    }

    // Nested conditions
    int age = 25;
    int hasLicense = 1;

    if (age >= 16) {
        if (hasLicense) {
            printf("Can drive\n");
        } else {
            printf("Need a license\n");
        }
    } else {
        printf("Too young to drive\n");
    }

    // Common C pitfall: = vs ==
    // if (x = 5) ← ASSIGNMENT, always true!
    // if (x == 5) ← COMPARISON, correct
    // Tip: write constants on left: if (5 == x) ← compiler catches if (5 = x)

    return 0;
}