How mobile number validation is done in C programming?

Answer 1

It depends what you mean by validation. If you mean the actual phone number itself, the best you can do is count the digits to ensure it is the correct length. But that will only tell that it could be a phone number, not that it is a phone number. You'd have to dial the number to check its actual validity.

If you actually mean the 15-digit IMEI number, that can be easily validated. The final digit (#15) is a checksum digit. To validate the IMEI, double every second digit. If the product is greater than 10, subtract 9 (same as adding the two digits together). Finally add all 15 digits together. If the sum is divisible by 10, the number is a valid IMEI number. An example implementation is shown:

#include

int main()

{

int IMEI[15];

int i = 0;

int sum = 0;

char cIMEI[16];

memset( &cIMEI[0], 0, 16 );

while( strlen( cIMEI ) != 15 )

{

std::cout << "Enter the 15-digit IMEI number: ";

std::cin.getline( cIMEI, 16, '\n' );

}

// Convert characters to integers (digits).

for( i=0; i<15; ++i)

IMEI[i] = (int) ( cIMEI[i] - '0');

// Iterate the digits.

for( i=0; i<15; ++i)

{

// For odd elements only (every 2nd digit).

if( i % 2 )

{

IMEI[i] *= 2; // Double the digit.

if( IMEI[i] > 9 ) // Is the product 10, 12, 14, 16 or 18?

IMEI[i] -= 9; // Add the 2 individual digits together.

}

// Update the sum.

sum += IMEI[i];

}

// Display the result:

std::cout << "The IMEI number is ";

if( sum % 10)

std::cout << "invalid!" << std::endl;

else

std::cout << "valid!" << std::endl;

return( 0 );

}