C Archives | 799 The Coder

C – Authentication Program with username and password

C-Authentication program will helps to add an authentic step before getting into your program. This can be used as a security check in any C program.

Customization In Code

In the given code for Authentication in C language, you can specify following properties/values as per your choice.

Username
Password
Number of maximum attempts

Source Code

#include< conio.h >
#include< stdio.h >
#include< dos.h >
#include< string.h >
int authenticate(char userName[], char password[]);
void main(){
 char password[20] = "password"; // set password
 char userName[20] = "userName"; // set userName
 if(authenticate(userName,password)){
  printf("\nAuthentication Successfull!");
 }else{
  printf("\nYou have attempted all tries, program will exit soon!!!");
  sleep(3);
  exit(1);
 }
 getch();
}
int authenticate(char userName[], char password[]){
 char ch;
 char currentUserName[20];
 char currentPassword[20];
 int i,attempts=1,userNameCorrect=1;
 int maxTry = 3;
 while(attempts < = maxTry){
  ch='\0';
  if(userNameCorrect){
   clrscr();
   printf("User Name : ");
   gets(currentUserName);
  }
  if(strcmp(currentUserName,userName)==0){
   userNameCorrect = 0;
   clrscr();
   printf("User Name : %s\n",currentUserName);
   printf("Password  : ");
   i=0;
   while(ch!=13){
    ch = getch();
    if(ch!=13 && ch!=8){
     putch('*');
     currentPassword[i]=ch;
     i++;
    }
   }
   currentPassword[i] = '\0';
   if(strcmp(currentPassword,password)==0){
    // Authentication is successfull;
    return 1;
   }else{
    printf("\nPassword incorrect!");
    getch();
    attempts++;
   }

  }else{
   attempts++;
   printf("User name incorrect!");
   getch();
  }
 }
 return 0;
}

#include< conio.h >

#include< stdio.h >

#include< dos.h >

#include< string.h >

int authenticate(char userName[], char password[]);

void main(){

char password[20] = "password"; // set password

char userName[20] = "userName"; // set userName

if(authenticate(userName,password)){

printf("\nAuthentication Successfull!");

}else{

printf("\nYou have attempted all tries, program will exit soon!!!");

sleep(3);

exit(1);

}

getch();

}

int authenticate(char userName[], char password[]){

char ch;

char currentUserName[20];

char currentPassword[20];

int i,attempts=1,userNameCorrect=1;

int maxTry = 3;

while(attempts < = maxTry){

ch='\0';

if(userNameCorrect){

clrscr();

printf("User Name : ");

gets(currentUserName);

}

if(strcmp(currentUserName,userName)==0){

userNameCorrect = 0;

clrscr();

printf("User Name : %s\n",currentUserName);

printf("Password : ");

i=0;

while(ch!=13){

ch = getch();

if(ch!=13 && ch!=8){

putch('*');

currentPassword[i]=ch;

i++;

}

currentPassword[i] = '\0';

if(strcmp(currentPassword,password)==0){

// Authentication is successfull;

return 1;

}else{

printf("\nPassword incorrect!");

getch();

attempts++;

}

}else{

attempts++;

printf("User name incorrect!");

getch();

}

return 0;

}

C – Guess the secret sentence character by character

Here you will get complete source code guessing a character in a secret sentence or word in C Programming language. you can set your secret message or sentence in the code and then you can tell your friend to start guessing that secret message after executing the code.

One of my Facebook Page’s fan Faster Msr posted this on my page, so I coded to implement this using C Programming language.

Source Code of Program.

/*
 Author - Nisar Ahmed.
 Date - 28 June 2015.
*/
#include < conio.h>
#include < stdio.h>
#include < string.h>
int main(){
 int i,totalTry=0,totalChar = 0, charCorrect = 0, charIncorrect = 0, score = 0;
 char displayMsg[80], orgMsglwr[80];
 char orgMsg[] = "C programming";
 char ch,temp;
 for(i=0;i< strlen(orgMsg);i++){
  orgMsglwr[i] = orgMsg[i] >= 97 ? orgMsg[i]-32 : orgMsg[i];
  if(orgMsg[i] == ' ')
   displayMsg[i] = ' ';
  else{
   displayMsg[i] = '*';
   totalChar++;
  }
 }
 displayMsg[i] = '\0';
 orgMsglwr[i]='\0';

 totalTry = totalChar; // Set accordingly
 textbackground(WHITE);
 textcolor(BLUE);
 while(charIncorrect < totalTry){
  clrscr();
  textcolor(RED);
  gotoxy(30,3);
  cprintf("799 Web Nixar's Coding");
  gotoxy(20,5);
  cprintf("The program finds character in sentence");
  gotoxy(10,7);
  cprintf("If any character is already found then it is disabled.");
  textcolor(YELLOW);
  gotoxy(25,9);
  cprintf("%s",displayMsg);
  gotoxy(10,11);
  textcolor(BLACK);
  cprintf("Please find character : ");
  ch = getch();
  cprintf("%c",ch);
  temp = ch >= 97 ? ch-32 : ch+32;
  if(ch == ' '|| ch =='\r' || strchr(displayMsg,ch) != NULL || strchr(displayMsg,temp) != NULL)
   continue;
  ch = ch>=97 ? ch-32 : ch;
  if(NULL == strchr(displayMsg,ch) && NULL != strchr(orgMsglwr,ch)){
   charCorrect++;
   score++;
   for(i=0;i< strlen(orgMsg);i++){
    // Below two lines convert the character to lowercase
    temp = orgMsg[i] >= 97 ? orgMsg[i]-32 : orgMsg[i];
    ch = ch >=97 ? ch-32 : ch;
    if(temp == ch){
     displayMsg[i] = orgMsg[i];
    }
   }
  }else{
   charIncorrect++;
  }
  gotoxy(10,15);
  cprintf("Message : ");
  textcolor(YELLOW);
  cprintf(displayMsg);
  textcolor(BLACK);
  gotoxy(10,17);
  cprintf("Character correct : %d",charCorrect);
  gotoxy(40,17);
  cprintf("Character incorrect : %d",charIncorrect);
  gotoxy(10,19);
  cprintf("Score : %d",score);
  gotoxy(10,21);
  if(NULL == strchr(displayMsg,'*'))
   break;
  if(charIncorrect != totalTry)
   cprintf("Press any key to continue...");
  else
   cprintf("Game Over!!!");
  getch();

 }
 if(totalTry != charIncorrect)
  cprintf("Hurray! You Won");
 getch();
 return 0;
}

Author - Nisar Ahmed.

Date - 28 June 2015.

#include < conio.h>

#include < stdio.h>

#include < string.h>

int main(){

int i,totalTry=0,totalChar = 0, charCorrect = 0, charIncorrect = 0, score = 0;

char displayMsg[80], orgMsglwr[80];

char orgMsg[] = "C programming";

char ch,temp;

for(i=0;i< strlen(orgMsg);i++){

orgMsglwr[i] = orgMsg[i] >= 97 ? orgMsg[i]-32 : orgMsg[i];

if(orgMsg[i] == ' ')

displayMsg[i] = ' ';

else{

displayMsg[i] = '*';

totalChar++;

}

displayMsg[i] = '\0';

orgMsglwr[i]='\0';

totalTry = totalChar; // Set accordingly

textbackground(WHITE);

textcolor(BLUE);

while(charIncorrect < totalTry){

clrscr();

textcolor(RED);

gotoxy(30,3);

cprintf("799 Web Nixar's Coding");

gotoxy(20,5);

cprintf("The program finds character in sentence");

gotoxy(10,7);

cprintf("If any character is already found then it is disabled.");

textcolor(YELLOW);

gotoxy(25,9);

cprintf("%s",displayMsg);

gotoxy(10,11);

textcolor(BLACK);

cprintf("Please find character : ");

ch = getch();

cprintf("%c",ch);

temp = ch >= 97 ? ch-32 : ch+32;

if(ch == ' '|| ch =='\r' || strchr(displayMsg,ch) != NULL || strchr(displayMsg,temp) != NULL)

continue;

ch = ch>=97 ? ch-32 : ch;

if(NULL == strchr(displayMsg,ch) && NULL != strchr(orgMsglwr,ch)){

charCorrect++;

score++;

for(i=0;i< strlen(orgMsg);i++){

// Below two lines convert the character to lowercase

temp = orgMsg[i] >= 97 ? orgMsg[i]-32 : orgMsg[i];

ch = ch >=97 ? ch-32 : ch;

if(temp == ch){

displayMsg[i] = orgMsg[i];

}

}else{

charIncorrect++;

}

gotoxy(10,15);

cprintf("Message : ");

textcolor(YELLOW);

cprintf(displayMsg);

textcolor(BLACK);

gotoxy(10,17);

cprintf("Character correct : %d",charCorrect);

gotoxy(40,17);

cprintf("Character incorrect : %d",charIncorrect);

gotoxy(10,19);

cprintf("Score : %d",score);

gotoxy(10,21);

if(NULL == strchr(displayMsg,'*'))

break;

if(charIncorrect != totalTry)

cprintf("Press any key to continue...");

else

cprintf("Game Over!!!");

getch();

}

if(totalTry != charIncorrect)

cprintf("Hurray! You Won");

getch();

return 0;

}

C program for all number conversion.

I have created a C program for all number conversion, its a small application using C language. I have used printf’s various format specifiers to minimize the code and utilizing the available features of printf function.

These are some of format specifiers used in the code.

%d => for signed decimal integer.
%o => unsigned octal integer.
%X => unsigned hexadecimal integer.

The number conversions supported by this code are listed below.

Binary to Octal
Binary to Decimal
Binary to Hexadecimal
Octal to Binary
Octal to Decimal
Octal to Hexadecimal
Decimal to Binary
Decimal to Octal
Decimal to Hexadecimal
Hexadecimal to Binary
Hexadecimal to Octal
Hexadecimal to Decimal

C program for all number conversion — All Number Conversions using C

#include< conio.h>
#include< stdio.h>
#include< math.h>
#include< string.h>

#define toBinary 1
#define toOctal 2
#define toDecimal 3
#define toHexadecimal 4

// Function to show the Converted number
void showConvertedNumber(int choice, int num){
	int i=0,sizeofInt;
	switch(choice){
		case toBinary :
			sizeofInt = sizeof(int)*8; // To take size of int in bits
			printf("####### Binary : ");
			for(i=0;i < sizeofInt; i++)
				printf("%d",(num << i & 1 << (sizeofInt-1)) ? 1 : 0);
			break;
		case toOctal :
			printf("####### Octal : %o",num);
			break;
		case toDecimal :
			printf("####### Decimal : %d",num);
			break;
		case toHexadecimal :
			printf("####### Hexadecimal : %X",num);
			break;
	}
	getch();
}
// Function to show the error message
void showError(){
	printf("####### Enter valid number! ");
	getch();
}
// Function to convert binary number to decimal
int getDecimal(char *binary){
	int i,decimal=0;
	for(i = strlen(binary)-1; i >= 0 ;i--){
		if(binary[i] == '1')
			decimal += (int) pow((double) 2, (double) (strlen(binary)-1 - i));
	}
	return decimal;
}
// Function to validate the binary string.
int validateBinary(char *binary){
    int valid = 1,i;
    for(i = 0 ; i < strlen(binary); i++){
	if(binary[i] == '1' || binary[i] == '0')
		continue;
	else{
		valid = 0;
		break;
	}
    }
    return valid;
}
void main(){
	int choice,num,innerChoice,valid;
	char binary[sizeof(int)];
	textmode(C40);
	textbackground(WHITE);
	textcolor(BLUE);
	do{
		clrscr();
		printf("####### 799 Web Nixar's Creation    ####");
		printf("________________________________________");
		printf("####### Number Conversion Menu      ####");
		printf("========================================");
		printf("====>   1.Binary to Octal           ####");
		printf("====>   2.Binary to Decimal         ####");
		printf("====>   3.Binary to Hexadecimal     ####");
		printf("________________________________________");
		printf("====>   4.Octal to Binary           ####");
		printf("====>   5.Octal to Decimal          ####");
		printf("====>   6.Octal to Hexadecimal      ####");
		printf("________________________________________");
		printf("====>   7.Decimal to Binary         ####");
		printf("====>   8.Decimal to Octal          ####");
		printf("====>   9.Decimal to Hexadecimal    ####");
		printf("________________________________________");
		printf("====>   10.Hexadecimal to Binary    ####");
		printf("====>   11.Hexadecimal to Octal     ####");
		printf("====>   12.Hexadecimal to Decimal   ####");
		printf("________________________________________");
		printf("====>   13.Exit                     ####");
		printf("========================================");
		printf("####### Enter your Choice : ");
		scanf("%d",&choice);
		switch(choice){
			case 1 :
			case 2 :
			case 3 :
				innerChoice = (choice == 1 ? 2 : choice == 2 ? 3 : 4);
				printf("####### Enter binary number : ");
				scanf("%s",binary);
				// validation
				valid = validateBinary(binary);
				if(0 == valid){
					showError();
					break;
				}
				num = getDecimal(binary);
				showConvertedNumber(innerChoice,num);
				break;
			case 4 :
			case 5 :
			case 6 :
				innerChoice =  (choice == 4 ? 1 : choice == 5 ? 3 : 4);
				printf("####### Enter octal number : ");

				valid = scanf("%o",&num);
				// validation
				if(0 == valid){
				      showError();
				      break;
				}
				showConvertedNumber(innerChoice,num);
				break;
			case 7 :
			case 8 :
			case 9 :
				innerChoice =  (choice == 7 ? 1 : choice == 8 ? 2 : 4);
				printf("####### Enter decimal number : ");
				valid = scanf("%d",&num);
				// validation
				if(0 == valid){
					showError();
					break;
				}
				showConvertedNumber(innerChoice,num);
				break;
				break;
			case 10:
			case 11:
			case 12:
				innerChoice =  (choice == 10 ? 1 : choice == 11 ? 2 : 3);
				printf("####### Enter Hexadecimal number : ");
				valid = scanf("%x",&num);
				// validation
				if(0 == valid){
					showError();
					break;
				}
				showConvertedNumber(innerChoice,num);
				break;
			case 13: exit(1);
				 break;
			default: printf("####### Enter valid choice ");
				 getch();
				 main();
				 break;
		}
	}while(1);
	getch();
}

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#include< conio.h>

#include< stdio.h>

#include< math.h>

#include< string.h>

#define toBinary 1

#define toOctal 2

#define toDecimal 3

#define toHexadecimal 4

// Function to show the Converted number

void showConvertedNumber(int choice, int num){

int i=0,sizeofInt;

switch(choice){

case toBinary :

sizeofInt = sizeof(int)*8; // To take size of int in bits

printf("####### Binary : ");

for(i=0;i < sizeofInt; i++)

printf("%d",(num << i & 1 << (sizeofInt-1)) ? 1 : 0);

break;

case toOctal :

printf("####### Octal : %o",num);

break;

case toDecimal :

printf("####### Decimal : %d",num);

break;

case toHexadecimal :

printf("####### Hexadecimal : %X",num);

break;

}

getch();

}

// Function to show the error message

void showError(){

printf("####### Enter valid number! ");

getch();

}

// Function to convert binary number to decimal

int getDecimal(char *binary){

int i,decimal=0;

for(i = strlen(binary)-1; i >= 0 ;i--){

if(binary[i] == '1')

decimal += (int) pow((double) 2, (double) (strlen(binary)-1 - i));

}

return decimal;

}

// Function to validate the binary string.

int validateBinary(char *binary){

int valid = 1,i;

for(i = 0 ; i < strlen(binary); i++){

if(binary[i] == '1' || binary[i] == '0')

continue;

else{

valid = 0;

break;

}

return valid;

}

void main(){

int choice,num,innerChoice,valid;

char binary[sizeof(int)];

textmode(C40);

textbackground(WHITE);

textcolor(BLUE);

do{

clrscr();

printf("####### 799 Web Nixar's Creation ####");

printf("________________________________________");

printf("####### Number Conversion Menu ####");

printf("========================================");

printf("====> 1.Binary to Octal ####");

printf("====> 2.Binary to Decimal ####");

printf("====> 3.Binary to Hexadecimal ####");

printf("________________________________________");

printf("====> 4.Octal to Binary ####");

printf("====> 5.Octal to Decimal ####");

printf("====> 6.Octal to Hexadecimal ####");

printf("________________________________________");

printf("====> 7.Decimal to Binary ####");

printf("====> 8.Decimal to Octal ####");

printf("====> 9.Decimal to Hexadecimal ####");

printf("________________________________________");

printf("====> 10.Hexadecimal to Binary ####");

printf("====> 11.Hexadecimal to Octal ####");

printf("====> 12.Hexadecimal to Decimal ####");

printf("________________________________________");

printf("====> 13.Exit ####");

printf("========================================");

printf("####### Enter your Choice : ");

scanf("%d",&choice);

switch(choice){

case 1 :

case 2 :

case 3 :

innerChoice = (choice == 1 ? 2 : choice == 2 ? 3 : 4);

printf("####### Enter binary number : ");

scanf("%s",binary);

// validation

valid = validateBinary(binary);

if(0 == valid){

showError();

break;

}

num = getDecimal(binary);

showConvertedNumber(innerChoice,num);

break;

case 4 :

case 5 :

case 6 :

innerChoice = (choice == 4 ? 1 : choice == 5 ? 3 : 4);

printf("####### Enter octal number : ");

valid = scanf("%o",&num);

// validation

if(0 == valid){

showError();

break;

}

showConvertedNumber(innerChoice,num);

break;

case 7 :

case 8 :

case 9 :

innerChoice = (choice == 7 ? 1 : choice == 8 ? 2 : 4);

printf("####### Enter decimal number : ");

valid = scanf("%d",&num);

// validation

if(0 == valid){

showError();

break;

}

showConvertedNumber(innerChoice,num);

break;

case 10:

case 11:

case 12:

innerChoice = (choice == 10 ? 1 : choice == 11 ? 2 : 3);

printf("####### Enter Hexadecimal number : ");

valid = scanf("%x",&num);

// validation

if(0 == valid){

showError();

break;

}

showConvertedNumber(innerChoice,num);

break;

case 13: exit(1);

break;

default: printf("####### Enter valid choice ");

getch();

main();

break;

}

}while(1);

getch();

}

Love and Friendship calculator using C/C++

Love and Friendship calculator is a small C or C++ application which implements a school-time logic. When we are in school time we play with our names and calculate some percentage. I also implemented one of them logic to calculate Love and friendship.

The Logic which i have implemented is as follows.

Two names n1 and n2 are taken from the user. And one choice for friendship or love calculation.
If user choose friendship then we make a string n1+ friend + n2.
If user choose love then we make a string n1 + love + n2.
Then we start manipulation over the concatenated string from left to right.
We count occurrence of each character (except space) until all characters are traversed and keep that count of each character in an array.
Now we have an array containing count of each character. now we perform operation on this array.
we start adding first element of array with last element of array, second element with second last element of the array and so on.
Keep continue the above step until we get array with only two elements.
Now we have percentage. if percentage is higher then 100% we manipulate it until we get percentage less than or equal to 100%.

/*
Author - Nisar Ahmed.
Description - It takes two names and then calculate Love and Friendship percentage of these names.
*/

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

int calcPercentage(int l,int h,int ar[]);

struct nameModel
{
    char name[100];
    int isCounted[100];
}nameObject;

int main(){
    textmode(C40);
    textbackground(GREEN);
    textcolor(WHITE);
    do{
        x:
        clrscr();
        int count,a=0,ar[20],i,j;
        char name1[40],ch,name2[40],choice;
        cout<<"\n";
        cout<<"------- 799 Web Nixar Creation ---------";
        cout<<"----------------------------------------";
        cout<<"|      * Welcome To Friendship *       |";
        cout<<"|       *  & Love Calculator  *        |";
        cout<<"----------------------------------------";
        cout<<"              1.Friendship              ";
        cout<<"              2.Love                    ";
        cout<<"              3.Exit                    ";
        cout<<"       Enter Your Choice                ";
        gotoxy(28,10);
        cin>>choice;
        switch(choice)
        {
            case '1':    
			cout<<"                                        ";
            cout<<"        ----------------------          ";
            cout<<"           Enter Your Name              ";
            gotoxy(17,14);
            gets(name1);
            cout<<"        ----------------------          ";
            cout<<"       Enter Your Friend's Name         ";
            gotoxy(17,17);
            gets(name2);
            cout<<"        ----------------------          ";
            break;
        case '2': 
			cout<<"                                        ";
            cout<<"        ----------------------          ";
            cout<<"           Enter Your Name              ";
            gotoxy(17,14);
            gets(name1);
            cout<<"        ----------------------          ";
            cout<<"        Enter Your Lover's Name         ";
            gotoxy(17,17);
            gets(name2);
            cout<<"        ----------------------          ";
            break;
        case '3':
			exit(1);
            break;
        default:
			cout<<"             Wrong Choice !!            ";
            goto x;
        }
        strlwr(name1);
        strlwr(name2);
        if(choice=='1')
            strcat(name1,"friend");
        else
            strcat(name1,"love");
        strcat(name1,name2);
        strcpy(nameObject.name,name1);
        for(i=0;i< strlen(name1);i++){
            nameObject.isCounted[i]=0;
        }
        for(i=0;i< strlen(nameObject.name);i++){
            if(nameObject.isCounted[i]==0){
                ch=nameObject.name[i];
                if(ch==' ')
                    continue;
                count=1;
                nameObject.isCounted[i]=1;
                for(j=i+1;j< strlen(nameObject.name);j++){
                    if(ch==nameObject.name[j]){
                        count+=1;
                        nameObject.isCounted[j]=1;
                    }
                }
                ar[a++]=count;
            }
        }
        gotoxy(18,19);
        cout<< calcPercentage(0,(a-1),ar) << "%\n\n\n";
        cout<< "########################################";
        getch();
    }while(1);
    return 0;
}
int calcPercentage(int l,int h,int ar[])
{
    int i,r=0,j,sum;
    if((l+h)%2 == 0){
        for(i=l,j=h;i < j;i++,j--)
            ar[r++]=ar[i]+ar[j];
        ar[r++]=ar[i];
    }
    else{
        for(i=l,j=h;i < j;i++,j--)
            ar[r++]=ar[i]+ar[j];
    }
    h=r-1;
    if(l+h > 1)
        calcPercentage(l,h,ar);
    else{
        sum=0;
        for(i=0;i < 2;i++){
        if(i==0)
            sum+=ar[i]*10;
        else
            sum+=ar[i];
        }
        while(sum > 100){
            sum = (sum%10)*10 +(sum/10);
        }
    return sum;
    }
}

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Author - Nisar Ahmed.

Description - It takes two names and then calculate Love and Friendship percentage of these names.

#include< conio.h>

#include< iostream.h>

#include< string.h>

#include< stdio.h>

#include< stdlib.h>

int calcPercentage(int l,int h,int ar[]);

struct nameModel

{

char name[100];

int isCounted[100];

}nameObject;

int main(){

textmode(C40);

textbackground(GREEN);

textcolor(WHITE);

do{

clrscr();

int count,a=0,ar[20],i,j;

char name1[40],ch,name2[40],choice;

cout<<"\n";

cout<<"------- 799 Web Nixar Creation ---------";

cout<<"----------------------------------------";

cout<<"| * Welcome To Friendship * |";

cout<<"| * & Love Calculator * |";

cout<<"----------------------------------------";

cout<<" 1.Friendship ";

cout<<" 2.Love ";

cout<<" 3.Exit ";

cout<<" Enter Your Choice ";

gotoxy(28,10);

cin>>choice;

switch(choice)

{

case '1':

cout<<" ";