This is my first year C project. TicTacToe game by c.

tictactoe.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>
#include <windows.h>
int password();
int pass_system();
void printBoard();
void change_player();
void input();
int mainInput(int pass);
void run_game();
int win();
void input();
int input_from_user();
void change_background_and_textColour();
void menu();
void go(int n);
void start_game();
void check_draw();
void draw_boarD();
void player_first();
void put_X_O(char ch,int pos);
void sub_main();
void main_s();
/* Global variables */
char board[9]= {'1','2','3','4','5','6','7','8','9'};
int password();
int pass_system();
int n,j=1;
char player='X';
char ch,ch1[80];
int i_for_loop,check_user_input_pass=-1;
int boarD[10] = {2,2,2,2,2,2,2,2,2,2};
int turn = 1,flag = 0;
int playeR,comp;
COORD coord= {0,0};
/* Global variables */

int main ()
{
    change_background_and_textColour();
    int i;
    for (;;)
    {
        system("cls");
        sub_main();
        getch();
        system("cls");
        check_user_input_pass=0;
        printf("Press 1 for play again\nPress 2 Exit\nInput : ");
        i=input_from_user();
        if (i==1)
        {
            check_user_input_pass++;
            for (i=0;i<9;i++)
            board[i]='1'+i;
            continue;
        }
        else break;
    }
    system("cls");
    printf("Thanks for playing :)\nBye Bye");
    getch();
    return 0;
}

/**
Testing data
1
674
1
1
2
4
5
1

1
674
1
1
2
4
5


*/
void sub_main()
{
    printf("Press 1 for play user vs user \nPress 2 for play user vs pc\nPromote : ");
    int userchoise;
    userchoise=input_from_user();
    if (userchoise==1 || userchoise==2)
    {
        if (!password(userchoise))
        {
            printf("The game is terminated");
            return 0;
        }
    }
    else
        printf("You can play");
    if (userchoise==1)
        run_game();
    else
    {
        main_s();
    }
}
void change_background_and_textColour()
{
    int value,value1;

    printf("Give input for change text color\nBackground change automatically\nPress");
    printf("\nBlack = 1\nGreen = 2\nAqua = 3\nRed = 4\nPurple = 5\nYellow = 6\nWhite = 7\nGray = 8\nLight Blue = 9\n");
    printf("Color = ");
    value=input_from_user();
    switch(value)
    {
    case 1 :
        system("COLOR 60");
        break;
    case 2 :
        system("COLOR 0A");
        break;
    case 3 :
        system("COLOR C3");
        break;
    case 4 :
        system("COLOR 74");
        break;
    case 5 :
        system("COLOR E5");
        break;
    case 6 :
        system("COLOR B6");
        break;
    case 7 :
        system("COLOR 17");
        break;
    case 8 :
        system("COLOR C8");
        break;
    case 9 :
        system("COLOR A9");
        break;

    }
    system("cls");
    check_user_input_pass++;

}

int password (int userchoise)         ///for password matching
{
    char pass[80]="674",pass1[80]="658";
    int increment=3;
    printf("Enter the password : ");
    pass_system();
    if (userchoise==1)
    {
        while (strcmp(pass,ch1) && increment>0)
        {
            if (increment==1)
            {
                printf("Sorry ^_^ .. Next time please\n");
                return 0;
            }
            system("cls");
            printf("You have %d chance left \n",increment-1);
            --increment;
            printf("Enter password : ");
            pass_system();

        }
        return 1;
    }
    else if (userchoise==2)
    {
        while (strcmp(pass1,ch1) && increment>0)
        {
            if (increment==1)
            {
                printf("Sorry ^_^ ..\n Next time please\n");
                return 0;
            }
            system("cls");
            printf("You have %d chance left \n",increment-1);
            --increment;
            printf("Enter password : ");
            pass_system();

        }
        return 1;
    }


}

int pass_system()    /// for password input
{
    i_for_loop=0;
    while ( (ch=getch()) !='\r'  && i_for_loop <79 ) ///scan single character but not displayed in console
    {
        printf("*");
        ch1[i_for_loop++]=ch; ///put the character into
    }
    ch1[i_for_loop]='\0';
    printf("\n");
    return ch1[i_for_loop];

}

void printBoard()
{
    system("cls");
    int i;
    printf("SIMPLE TIC TAC TOE GAME By C\n\tUSER VS USER\n\n");
    printf("+*-*+*-*+*-*+\n");
    for (i=0; i<9; i++)
    {
        if (i!=0 && i%3==0)
            printf("\n+---+---+---+\n|");
        if (i==0)
            printf("|");
        printf(" %c |",board[i]);


    }
    printf("\n+*-*+*-*+*-*+\n");

}

void call_error()
{
    printf("Field is already in use try again!");
    input();

}
int mainInput(int pass)
{
    if (pass==1)
    {

        if (board[pass-1]=='1')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
    else if (pass==2)
    {

        if (board[pass-1]=='2')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
    else if (pass==3)
    {

        if (board[pass-1]=='3')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
    else if (pass==4)
    {

        if (board[pass-1]=='4')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
    else if (pass==5)
    {

        if (board[pass-1]=='5')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
    else if (pass==6)
    {

        if (board[pass-1]=='6')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
    else if (pass==7)
    {

        if (board[pass-1]=='7')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
    else if (pass==8)
    {

        if (board[pass-1]=='8')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
    else if (pass==9)
    {

        if (board[pass-1]=='9')
        {
            board[pass-1]=player;
        }
        else
            call_error();
    }
}

int input_from_user()
{
    char a[4];
    int k=0,g;
    while (k==0)
    {

        fgets(a, 3, stdin);
        fflush(stdin);

        if(strlen(a) != 2)
        {
            printf("Invalid input\n");
            printf("Input again : ");
            continue;
        }

        if( sscanf(a, "%d", &g) != 1)
        {
            printf("Invalid input\n");
            printf("Input again : ");
            continue;
        }
        if (check_user_input_pass!=0)
            if( g < 1 || g > 9)
            {
                printf("Invalid range\n");
                printf("Input again : ");

                continue;
            }
        if (check_user_input_pass==0)
            if( g < 1 || g > 2)
            {
                printf("Invalid range\n");
                printf("Input again : ");

                continue;
            }

        k = 1;
    }
    return g;
}
void input()
{
    int g,k=0;
    printf("\n\nIts player %d trun who can put %c\nPress the number of the board : ",j,player);
    mainInput(input_from_user());
}
void change_player()
{
    if (player == 'X')
    {
        player = 'O';
        j=2;
    }

    else
    {
        player = 'X';
        j=1;
    }
}
int win()
{
    if (( board[0]=='X' && board[1]=='X' && board[2]=='X' ) || ( board[3]=='X' && board[4]=='X' && board[5]=='X' )
            ||( board[6]=='X' && board[7]=='X' && board[8]=='X' ) || ( board[0]=='X' && board[3]=='X' && board[6]=='X' )
            ||( board[1]=='X' && board[4]=='X' && board[7]=='X' ) || ( board[2]=='X' && board[5]=='X' && board[8]=='X' )
            ||( board[0]=='X' && board[4]=='X' && board[8]=='X' ) || ( board[2]=='X' && board[4]=='X' && board[6]=='X' ))
        return 1;
    if (( board[0]=='O' && board[1]=='O' && board[2]=='O' ) || ( board[3]=='O' && board[4]=='O' && board[5]=='O' )
            ||( board[6]=='O' && board[7]=='O' && board[8]=='O' ) || ( board[0]=='O' && board[3]=='O' && board[6]=='O' )
            ||( board[1]=='O' && board[4]=='O' && board[7]=='O' ) || ( board[2]=='O' && board[5]=='O' && board[8]=='O' )
            ||( board[0]=='O' && board[4]=='O' && board[8]=='O' ) || ( board[2]=='O' && board[4]=='O' && board[6]=='O' ))
        return 2;
    return 3;
}
void run_game()
{
    n=0;
    printBoard();
    printf("\n\nPress 1 for playing with O\nPress 2 for playing with X\n\nInput : ");
    int m=input_from_user();
    if (m==1)
        player='O';
    else if (m==2)
        player='X';
    check_user_input_pass++;
    system("cls");
    printBoard();
    while(1)
    {
        n++;
        input();
        printBoard();
        change_player();
        if (n>4)
        {
            if (win()==1)
            {
                printf("\n****** 1st player win who is 'X' ******\n");
                break;
            }
            else if(win()==2)
            {
                printf("\n****** 2nd player win who is 'O' ******\n");
                break;
            }
            else if (win()==3 && n==9)
            {
                printf("\n****** The game is draw ******\n");
                break;
            }
        }

    }
}

// Program is finished for user vs user


void gotoxy(int x,int y)
{
    coord.X=x;
    coord.Y=y;
    SetConsoleCursorPosition(GetStdHandle(STD_OUTPUT_HANDLE),coord);
}



void main_s()
{
    system("cls");
    menu();
    getch();

}

void menu()
{
    int choice;
    system("cls");
    printf("\n--------Your Choice--------");
    printf("\n1 : Play with X");
    printf("\n2 : Play with O");
    printf("\n3 : Exit");
    printf("\nEnter your choice:>");
    scanf("%d",&choice);
    turn = 1;
    switch (choice)
    {
    case 1:
        playeR = 1;
        comp = 0;
        player_first();
        break;
    case 2:
        playeR = 0;
        comp = 1;
        start_game();
        break;
    case 3:
        exit(1);
    default:
        menu();
    }
}

int make2()
{
    if(boarD[5] == 2)
        return 5;
    if(boarD[2] == 2)
        return 2;
    if(boarD[4] == 2)
        return 4;
    if(boarD[6] == 2)
        return 6;
    if(boarD[8] == 2)
        return 8;
    return 0;
}

int make4()
{
    if(boarD[1] == 2)
        return 1;
    if(boarD[3] == 2)
        return 3;
    if(boarD[7] == 2)
        return 7;
    if(boarD[9] == 2)
        return 9;
    return 0;
}

int posswin(int p)
{
// p==1 then X   p==0  then  O
    int i;
    int check_val,pos;

    if(p == 1)
        check_val = 18;
    else
        check_val = 50;

    i = 1;
    while(i<=9)//row check
    {
        if(boarD[i] * boarD[i+1] * boarD[i+2] == check_val)
        {
            if(boarD[i] == 2)
                return i;
            if(boarD[i+1] == 2)
                return i+1;
            if(boarD[i+2] == 2)
                return i+2;
        }
        i+=3;
    }

    i = 1;
    while(i<=3)//column check
    {
        if(boarD[i] * boarD[i+3] * boarD[i+6] == check_val)
        {
            if(boarD[i] == 2)
                return i;
            if(boarD[i+3] == 2)
                return i+3;
            if(boarD[i+6] == 2)
                return i+6;
        }
        i++;
    }

    if(boarD[1] * boarD[5] * boarD[9] == check_val)
    {
        if(boarD[1] == 2)
            return 1;
        if(boarD[5] == 2)
            return 5;
        if(boarD[9] == 2)
            return 9;
    }

    if(boarD[3] * boarD[5] * boarD[7] == check_val)
    {
        if(boarD[3] == 2)
            return 3;
        if(boarD[5] == 2)
            return 5;
        if(boarD[7] == 2)
            return 7;
    }
    return 0;
}

void go(int n)
{
    if(turn % 2)
        boarD[n] = 3;
    else
        boarD[n] = 5;
    turn++;
}

void player_first()
{
    int pos;

    check_draw();
    draw_boarD();
    gotoxy(30,18);
    printf("Your Turn :> ");
    scanf("%d",&pos);

    if(boarD[pos] != 2)
        player_first();

    if(pos == posswin(player))
    {
        go(pos);
        draw_boarD();
        gotoxy(30,20);
//textcolor(128+RED);
        printf("playeR Wins");
        getch();
        exit(0);
    }

    go(pos);
    draw_boarD();
    start_game();
}

void start_game()
{
// p==1 then X   p==0  then  O
    if(posswin(comp))
    {
        go(posswin(comp));
        flag = 1;
    }
    else if(posswin(player))
        go(posswin(player));
    else if(make2())
        go(make2());
    else
        go(make4());
    draw_boarD();

    if(flag)
    {
        gotoxy(30,20);
//textcolor(128+RED);
        printf("Computer wins");
        getch();
    }
    else
        player_first();
}

void check_draw()
{
    if(turn > 9)
    {
        gotoxy(30,20);
//textcolor(128+RED);
        printf("Game Draw");
        getch();
        exit(0);
    }
}

void draw_boarD()
{
    int j;

    for(j=9; j<17; j++)
    {
        gotoxy(35,j);
        printf("|       |");
    }
    gotoxy(28,11);
    printf("-----------------------");
    gotoxy(28,14);
    printf("-----------------------");

    for(j=1; j<10; j++)
    {
        if(boarD[j] == 3)
            put_X_O('X',j);
        else if(boarD[j] == 5)
            put_X_O('O',j);
    }
}

void put_X_O(char ch,int pos)
{
    int m;
    int x = 31, y = 10;

    m = pos;

    if(m > 3)
    {
        while(m > 3)
        {
            y += 3;
            m -= 3;
        }
    }
    if(pos % 3 == 0)
        x += 16;
    else
    {
        pos %= 3;
        pos--;
        while(pos)
        {
            x+=8;
            pos--;
        }
    }
    gotoxy(x,y);
    printf("%c",ch);
}