I am learning c

i just started watching a c tutorial by bro code because i wanna learn

here is a program i just made earlier

// c langauge basic one user login system

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

char login(char input_user[], char input_password[], char user[], char pass[]) {
    if (strcmp(input_user, user) == 0 && strcmp(input_password, pass) == 0) {
        return printf("\n\nWelcome, %s!\n\n", user);
    }
    else {
        system("clear");
        return printf("invalid login details.\n");
    }
}

int main() {
    char input_user[800];
    char input_pass[800];
    char user[] = "username";
    char pass[] = "password";
    
    printf("\n\nusername: ");
    scanf("%s", &input_user);
    printf("\npassword: ");
    scanf("%s", &input_pass);
    
    login(input_user, input_pass, user, pass);
}

if anyone has any learning tips please lmk.