User Authentication Program in C

This is a C program to illustrate user authentication.

Problem Description

This C program asks for the user name & password and displays the same to illustrate user authentication.

Problem Solution

1. Take the user name & password as input.
2. Print the each character of password as * while receiving it.
3. Now print the original password and exit.

Program/Source Code

Here is source code of the C program to illustrate user authentication. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
/*
```

 * C program is to illustrate how user authentication is done.

 * Program asks for the user name and password and displays

```
 * the password as '*' character
```
```
 */
```
```
#include <stdio.h>
```
```
 
```
```
void main()
```
```
{
```
```
	char password[10], username[10], ch;
```
```
	int i;
```
```
 
```
```
	printf("Enter User name: ");
```
```
	gets(username);
```

	printf("Enter the password < any 8 characters>: ");

```
	for (i = 0; i < 8; i++)
```
```
	{
```
```
            ch = getchar();
```
```
            password[i] = ch;
```
```
            ch = '*' ;
```
```
            printf("%c", ch);
```
```
	}
```
```
        password[i] = '\0';
```

	/*  Original password can be printed, if needed */

```
	printf("\n Your password is :");
```
```
	for (i = 0; i < 8; i++)
```
```
	{
```
```
            printf("%c", password[i]);
```
```
	}
```
```
}
```

Program Explanation

1. Take the username as input and store it in the array username[].
2. Using for loop take the each character of password as input and store it in the array password[] and consecutively print it as ‘*’.
3. Print the array password[] as output and exit.

Runtime Test Cases

 
Enter User name: rajaraman
Enter the password <any 8 characters>: shashi12
********
Your password is :shashi12

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