it’s only my second code in C so far. I’ve some knowledge about this language, dynamic memory allocation etc. but I’m still far to be good in it. Earlier I used to program in Java, so I could have passed some habits from there. In general – what should I change to make this code somehow more perfect, what I shouldn’t do and what practices should be cultivated by me?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdbool.h>
#include <time.h>
#define BASE_DECIMAL 10
#define ID_LENGTH 5
#define MAX_FNAME_LENGTH 16
#define MAX_SNAME_LENGTH 32
#define MAX_PHONENUMBER_LENGTH 15
#define BUFFER_SIZE 256
//colors
#define ANSI_COLOR_RED "x1b(31m"
#define ANSI_COLOR_MAGENTA "x1b(35m"
#define ANSI_COLOR_CYAN "x1b(36m"
#define ANSI_COLOR_RESET "x1b(0m"
//prototypes
char* inputFirstName();
char* inputSurname();
char* inputPhoneNumber();
bool searchDuplicatedNumber( FILE *fp, char* search_Number );
char* checkConditions( FILE *fp );
char* ordinals( int i );
char* generateID();
FILE *checkInAllContacts();
void addNewContact( char* path, FILE *allContacts );
void addToAllContacts( char* path );
void showContactBasedOnPath( char* path );
int main( int argC, char* argV() ) {
//declare
char* id;
char option;
char* path_to_specific_file;
//allocate
id = malloc(ID_LENGTH * sizeof(char));
path_to_specific_file = malloc(ID_LENGTH * sizeof(char));
//check
if( id == NULL || path_to_specific_file == NULL) {
puts( "Memory allocation failed" );
return 0;
}
do{
printf( "ntt***Contact management system***n1. Add new contactn2. Show all contactsn3. Show specific contactn*Press 'q' to exit*n" );
fgets( &option, 3, stdin );
//assign
id = generateID();
//MENU
switch(option) {
case '1':
addNewContact(id, checkInAllContacts());
fclose(checkInAllContacts());
addToAllContacts(id);
free(id);
break;
case '2':
showContactBasedOnPath("All_Contacts.txt");
break;
case '3': //I know it can be probably achieved in different way
do{
puts( "Input path to file(based on given id!): ");
fgets( path_to_specific_file, (ID_LENGTH + 1), stdin );
showContactBasedOnPath(path_to_specific_file);
}while((getchar()) != 'n');
free(path_to_specific_file);
break;
case 'q':
printf(ANSI_COLOR_RED "nExiting...n" ANSI_COLOR_RESET);
exit(0);
default:
puts( "Undefined option!" );
break;
}
}while(1);
return 0;
}
//functions-----------------------
char* inputFirstName() {
char* name;
name = (char*) malloc( MAX_FNAME_LENGTH * sizeof(char) );
if( name == NULL ) {
puts( "Memory allocation failed - inputFirstName" );
exit( EXIT_FAILURE );
}
printf( "nn%s: ", "First name" );
fgets( name, MAX_FNAME_LENGTH, stdin );
return name;
}
char* inputSurname() {
char* sName;
sName = (char*) malloc( MAX_SNAME_LENGTH * sizeof(char) );
if( sName == NULL ) {
puts( "Memory allocation failed - inputSurname" );
exit( EXIT_FAILURE );
}
printf( "n%s: ", "Surname");
fgets( sName, MAX_SNAME_LENGTH, stdin );
return sName;
}
//phone number functions
char* inputPhoneNumber() {
char* phoneNumber;
phoneNumber = (char*) malloc( MAX_PHONENUMBER_LENGTH * sizeof(char) );
if( phoneNumber == NULL ) {
puts( "Memory allocation failed - inputPhoneNumber" );
exit( EXIT_FAILURE );
}
printf( "n%s: ", "Phone number" );
fgets( phoneNumber, MAX_PHONENUMBER_LENGTH, stdin );
return phoneNumber;
}
//search for duplicates
bool searchDuplicatedNumber(FILE *fp, char* search_Number) {
char* properties = (char*) malloc( BUFFER_SIZE * sizeof(char) );
if( properties == NULL ) {
puts( "Memory allocation failed - searchDuplicatedNumber" );
exit( EXIT_FAILURE );
}
//point to character
char *ptc;
while( ( fgets(properties, BUFFER_SIZE, fp) ) != NULL ) {
ptc = strstr(properties, search_Number);
if( ptc != NULL) {
return true;
}
}
free(properties);
return false;
}
//check if p.number meets all conditions
char* checkConditions(FILE *fp) {
char continue_Question;
char* phone_Number;
char* which_Ordinal;
phone_Number = (char*) malloc( MAX_PHONENUMBER_LENGTH * sizeof(char) );
which_Ordinal = (char*) malloc( 2 * sizeof(char) );
if( phone_Number == NULL || which_Ordinal == NULL ) {
puts( "Memory allocation failed - checkConditions" );
exit( EXIT_FAILURE );
}
phone_Number = inputPhoneNumber();
//check if it has character
for(int i = 0; i < strlen(phone_Number) - 1; ++i) {
if( !isdigit( phone_Number(i) ) ){
which_Ordinal = ordinals(i + 1);
printf( "nDetected error in input at %d%s positionnTry againn"
, i + 1, which_Ordinal);
//use recursion to make user provide correct input
return checkConditions(fp);
}
}
free(which_Ordinal);
//check for duplicated number
if( searchDuplicatedNumber(fp, phone_Number) ) {
printf( "nPhone number -> %s is assigned to another contact!n", phone_Number );
//if user accidentally provided phone number that already exist in contacts
//ask him if he wants to continue
printf( "nWould you like to continue?(Y/N) " );
fgets(&continue_Question, 3, stdin);
if(continue_Question == 'Y' || continue_Question == 'y') {
return checkConditions(fp);
}
else {
exit(0);
}
}
return phone_Number;
}
//add ordinals to the number so it'd be grammatically correct
char* ordinals( int i ) {
switch(i) {
case 1:
return "st";
break;
case 2:
return "nd";
break;
case 3:
return "rd";
break;
default:
return "th";
break;
}
}
//generate unique id for each contact
char* generateID() {
srand(time(NULL));
char* str_id = malloc(4 * sizeof(char));
if( str_id == NULL ) {
puts( "Memory allocation failed - generateID" );
exit( EXIT_FAILURE );
}
sprintf(str_id, "%d", (rand() % (99999 - 10000 + 1)) + 10000);
return str_id;
}
//files handling functions
//needed to look for duplicates
FILE *checkInAllContacts() {
FILE *fp;
fp = fopen( "All_Contacts.txt", "r");
if( fp == NULL ) {
printf( "nCould not open filen" );
exit( EXIT_FAILURE );
}
return fp;
}
//add new contact
void addNewContact( char* path, FILE *allContacts ) {
FILE *fp;
fp = fopen(path, "w");
if(fp == NULL) {
printf( "nUnable to create filen" );
exit( EXIT_FAILURE );
}
//get user input
char* f_Name;
char* surname;
char* ph_Number;
//allocate memory
f_Name = (char*) malloc(MAX_FNAME_LENGTH * sizeof(char));
surname = (char*) malloc(MAX_SNAME_LENGTH * sizeof(char));
ph_Number = malloc(MAX_PHONENUMBER_LENGTH * sizeof(ph_Number));
//check allocation
if(f_Name == NULL || surname == NULL || ph_Number == NULL) {
puts( "Memory allocation failed - addNewContact" );
exit( EXIT_FAILURE );
}
//assign functions to variables
f_Name = inputFirstName();
surname = inputSurname();
ph_Number = checkConditions(allContacts);
printf( "nGenerated id: %sn", path );
//add them to file
fprintf( fp, "nFirst name: %s", f_Name );
fprintf( fp, "nSurname: %s", surname );
fprintf( fp, "nPhone number: %s", ph_Number );
fprintf( fp, "nid: %sn", path );
//free memory and close file
free(f_Name);
free(surname);
free(ph_Number);
fclose(fp);
}
void addToAllContacts( char* path ) {
FILE *fpS, *fpD;
//buffer
char putIn;
fpS = fopen(path, "r");
fpD = fopen("All_Contacts.txt", "a");
if( fpS == NULL || fpD == NULL ) {
puts( "File not found - appending" );
exit( EXIT_FAILURE );
}
//add line to make it more readable
fprintf(fpD, "n----------------------------------------n");
//get text from source
while ( (putIn = fgetc( fpS )) != EOF ) {
//put it to destination file
fputc(putIn, fpD);
}
fclose(fpS);
fclose(fpD);
}
void showContactBasedOnPath( char* path ) {
FILE* fp;
char char_from_file;
fp = fopen(path, "r");
//check if exist
if( !fp ) {
puts( "n**File not found**n" );
return;
}
while( (char_from_file = fgetc(fp)) != EOF ) {
printf(ANSI_COLOR_CYAN "%c" ANSI_COLOR_RESET , char_from_file );
}
fclose(fp);
}
Probably some functions could be scaled into one, but tbh structure of this code is quite easy to get with, so that’s why I did not change it. Also I’m aware of it that if memory won’t be allocated or file would be NULL then program is gonna exit-crush. I’ll change it later.
