C PROGRAM! Hello! Can you help me to find the problem here? It prints "Its not valid" for every card number. This is the problem of Hans Luhn of IBM proposed an algorithm for validating credit card numbers.

#include #include #include bool isValid (char cardNumber [] ){ int l=strlen(cardNumber); if(l>=13 && l<=16) return true; else return false; }

int getDigit (int number){ int val, total=0; while(number>0){ val=number%10; total+=val; number=number/10; } if(total>10){ getDigit(total); } return total; } int sumOfOddPlace(char cardNumber [] ){ int l=(unsigned)strlen(cardNumber); int sum_odd=0; for(int i=l-1; i>=0;i=i-2){ sum_odd+=(cardNumber[i]-'0'); } return sum_odd; }

int sumOfDoubleEvenPlace (char cardNumber [] ){ int l=(unsigned)strlen(cardNumber); int sum_even=0,val; for(int i=l-2; i>=0; i=i-2){ val=(cardNumber[i]-'0')*2; if(val>=10){ sum_even+=getDigit(val); } else sum_even+=val; } return sum_even; }

int main() { char cardnum[16]; printf("Enter card number: "); scanf("%lld", &cardnum);

int sumOdd,sumEven,total; bool status; status=isValid(cardnum); sumOdd=sumOfOddPlace(cardnum); sumEven=sumOfDoubleEvenPlace(cardnum); total=sumOdd+sumEven; if(status && total%10 == 0){ printf("It is valid"); } else { printf("It is not valid"); }}