[C言語] switch文で文字列を扱う方法と代替手段

#include <stdio.h>
int main() {
    char *str = "example";
    switch (str) { // コンパイルエラー
        case "example":
            printf("This is an example.\n");
            break;
        default:
            printf("Default case.\n");
    }
    return 0;
}

#include <stdio.h>
#include <string.h>
int main() {
    char *str = "example";
    if (strcmp(str, "example") == 0) {
        printf("This is an example.\n");
    } else {
        printf("This is not an example.\n");
    }
    return 0;
}

#include <stdio.h>
#include <string.h>
int main() {
    char *str1 = "apple";
    char *str2 = "banana";
    int result = strcmp(str1, str2);
    if (result == 0) {
        printf("The strings are equal.\n");
    } else if (result < 0) {
        printf("The first string is less than the second string.\n");
    } else {
        printf("The first string is greater than the second string.\n");
    }
    return 0;
}

#include <stdio.h>
#include <string.h>
int main(int argc, char *argv[]) {
    if (argc > 1) {
        if (strcmp(argv[1], "start") == 0) {
            printf("Program started.\n");
        } else if (strcmp(argv[1], "stop") == 0) {
            printf("Program stopped.\n");
        } else {
            printf("Unknown command: %s\n", argv[1]);
        }
    } else {
        printf("No command provided.\n");
    }
    return 0;
}

$ ./program start
Program started.

#include <stdio.h>
#include <string.h>
void displayMenu() {
    printf("1. Start\n");
    printf("2. Stop\n");
    printf("3. Exit\n");
}
int main() {
    char choice[10];
    while (1) {
        displayMenu();
        printf("Enter your choice: ");
        scanf("%s", choice);
        if (strcmp(choice, "1") == 0) {
            printf("Starting...\n");
        } else if (strcmp(choice, "2") == 0) {
            printf("Stopping...\n");
        } else if (strcmp(choice, "3") == 0) {
            printf("Exiting...\n");
            break;
        } else {
            printf("Invalid choice.\n");
        }
    }
    return 0;
}

#include <stdio.h>
#include <string.h>
void parseConfigLine(char *line) {
    char key[50], value[50];
    sscanf(line, "%49[^=]=%49s", key, value);
    printf("Key: %s, Value: %s\n", key, value);
}
int main() {
    char *configLines[] = {
        "username=admin",
        "password=1234",
        "timeout=30"
    };
    for (int i = 0; i < 3; i++) {
        parseConfigLine(configLines[i]);
    }
    return 0;
}

Key: username, Value: admin
Key: password, Value: 1234
Key: timeout, Value: 30