How to write a id and password validation program in C

Understanding ID and Password Validation

• Validates user-entered information against pre-defined credentials.
• Ensures only authorized users can access data or systems.
• Enhances security and prevents unauthorized access.

Key Concepts Involved

• Input/Output: Use printf and scanf for user interaction.
• String Manipulation: Employ strcmp to compare strings for validation.
• Conditional Statements: Implement if-else to control program flow based on validation results.

Step-by-Step Guide

1. Include Necessary Header:

C

#include <stdio.h>

2. Declare Variables:

C

char actualId[50], actualPassword[50], enteredId[50], enteredPassword[50];

3. Store Actual Credentials:

C

strcpy(actualId, "your_actual_id");
strcpy(actualPassword, "your_actual_password");

4. Prompt for User Input:

C

printf("Enter your ID: ");
scanf("%s", enteredId);
printf("Enter your password: ");
scanf("%s", enteredPassword);

5. Validate ID and Password:

C

if (strcmp(actualId, enteredId) == 0 && strcmp(actualPassword, enteredPassword) == 0) {
    printf("Login successful!\n");
} else {
    printf("Invalid ID or password.\n");
}

Full Code:

C

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

int main() {
    char actualId[50] = "your_actual_id";
    char actualPassword[50] = "your_actual_password";
    char enteredId[50], enteredPassword[50];

    printf("Enter your ID: ");
    scanf("%s", enteredId);
    printf("Enter your password: ");
    scanf("%s", enteredPassword);

    if (strcmp(actualId, enteredId) == 0 && strcmp(actualPassword, enteredPassword) == 0) {
        printf("Login successful!\n");
    } else {
        printf("Invalid ID or password.\n");
    }

    return 0;
}

Explanation:

1. stdio.h provides input/output functions, and string.h offers string manipulation functions.
2. Variables store actual credentials and user input.
3. printf prompts for input, and scanf stores user input in variables.
4. strcmp compares strings: 0 indicates a match, non-zero indicates a mismatch.
5. if-else conditionally grants access or displays an error message.

Customization and Enhancements:

• Store credentials securely (avoid hardcoding).
• Implement password masking for privacy.
• Set limits on login attempts.
• Add password complexity checks (length, special characters).
• Handle case-insensitive passwords.
• Provide password reset functionality.

Conclusion:

This basic program demonstrates ID and password validation in C. Build upon this foundation for robust authentication systems, ensuring data security and user privacy.