main.c

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

/* BUGS | IMPROVEMENTS :
 * pass pointers to functions instead of the whole array/variable
 * review the random picker functions
*/


struct input_length {
    int numbers;
    int characters;
    int symbols;
};


int* random_numbers(int *random_n,struct input_length s0) {
    srand(time(nullptr));

    for (int i = 0; i < s0.numbers; i++) {
        random_n[i] = rand() % 10;
    }

    return random_n;
}


char* random_characters(char *random_char,struct input_length s1) {
    srand(time(nullptr));
    char randomletter;

    for (int i=0; i< s1.characters; i++) {
        randomletter = 'a' + rand() % 26;
        random_char[i]=randomletter;
    }
    random_char[s1.characters]='\0';

    return random_char;
}


char* random_symbols(char *random_symb,char symbols_list_text[2],struct input_length s2) {
    srand(time(nullptr));
    int random;

    for (int i = 0; i < s2.symbols; i++) {
        random = rand()%32;
        random_symb[i]=symbols_list_text[random];
    }
    random_symb[s2.symbols]='\0';

    return random_symb;
}


struct input_length user_input() {
    struct input_length input;

    printf("\nINFO: the password length will be the sum of the numbers, characters and symbols.\n");
    printf("\nINFO: the amount of numbers, characters and symbols is approximate, because of the random algorithm.\n");
    printf("\nPlease check the DISCLAIMER and LICENSE.\n");

    printf("\nEnter the amount of numbers:");
    scanf("%d",&input.numbers);

    printf("\nEnter the amount of characters:");
    scanf("%d",&input.characters);

    printf("\nEnter the amount of symbols:");
    scanf("%d",&input.symbols);

    return input;
}


void print_password(char *password,struct input_length input) { // prints the length, password, numbers and ASCII codes for testing
    int password_length=input.numbers+input.characters+input.symbols; // the syntax is print_password(password,input)

    printf("\nLength: %d\nPassword:\n",password_length); // the parameters "password" and "input" are from the "generate_password" function

    for (int i=0;i<password_length; i++) {
        printf("[%d]",password[i]);
    }
    printf("\n");

    for (int i=0;i<password_length; i++) {
        printf("[%c]",password[i]);
    }
    printf("\n");
}


int check_old_positions(int *old_position,int position,int old_length) {
    for (int i=0; i < old_length; i++) {
        if (*(old_position+i) == position) {
            return 0;
        }
    }
    return 1;
}


char* generate_password(char *password,int *numbers_list,char *characters_list,char *symbols_list,struct input_length input) {
    srand(time(nullptr));

    int length=input.numbers+input.characters+input.symbols;
    int index_list=0;
    int old_positions[length];
    int position;
    int check=0;
    int old_length=0;

    for (int i=0;i < input.numbers;i++) {
        while (check!=1) {
            position=rand() % length;
            check=check_old_positions(&old_positions[0],position,old_length);
        }

        old_positions[index_list]=position;
        password[position]=(char)(numbers_list[rand() % input.numbers]+'0');

        index_list=index_list+1;
        check=0;
        old_length=old_length+1;
    }

    for (int i=0;i < input.characters;i++) {
        while (check!=1) {
            position=rand() % length;
            check=check_old_positions(&old_positions[0],position,old_length);
        }

        old_positions[index_list]=position;

        password[position]=characters_list[rand() % input.characters];
        index_list=index_list+1;
        check=0;
        old_length=old_length+1;
    }

    for (int i=0;i < input.symbols;i++) {
        while (check!=1) {
            position=rand() % length;
            check=check_old_positions(&old_positions[0],position,old_length);
        }

        old_positions[index_list]=position;
        password[position]=symbols_list[rand() % input.symbols];

        index_list=index_list+1;
        check=0;
        old_length=old_length+1;
    }

    password[length]='\0';

    return password;
}


int main() {

    struct input_length user_input_length;

    char list_text[] = "!@#$%^&*()_+-=[]\\{}|;':,.<>/?`~\"";
    user_input_length=user_input();

    int* numbers_list = malloc(user_input_length.numbers * sizeof(int));
    char* characters_list = malloc(user_input_length.characters * sizeof(char));
    char* symbols_list = malloc(user_input_length.symbols * sizeof(char));
    char* finalPassword=malloc((user_input_length.numbers+user_input_length.characters+user_input_length.symbols) * sizeof(char));

    numbers_list=random_numbers(numbers_list,user_input_length);
    characters_list=random_characters(characters_list,user_input_length);
    symbols_list=random_symbols(symbols_list,list_text,user_input_length);

    finalPassword=generate_password(finalPassword,numbers_list,characters_list,symbols_list,user_input_length);
    printf("Password:%s\n",finalPassword);

    free(numbers_list);
    free(characters_list);
    free(symbols_list);
    free(finalPassword);
    return 0;
}