Roman numeral addition

[Mr potato19]

#include<stdio.h>

#include<string.h>



int digit(char);

void decimal2roman(int num){
int decimal[] = {1000,900,500,400,100,90,50,40,10,9,5,4,1}; //base values
char *symbol[] = {"M","CM","D","CD","C","XC","L","XL","X","IX","V","IV","I"}; //roman symbols
int i = 0;

while(num){ //repeat process until num is not 0
while(num/decimal[i]){ //first base value that divides num is largest base value
printf("%s",symbol[i]); //print roman symbol equivalent to largest base value
num -= decimal[i]; //subtract largest base value from num
}
i++; //move to next base value to divide num
}
}

int main(){



char roman_Number[1000];

int i=0;

long int number =0;



printf("Enter FIRST roman number (Valid digits are I, V, X, L, C, D, M): \n");

scanf("%s",roman_Number);



while(roman_Number[i]){



if(digit(roman_Number[i]) < 0){

printf("Invalid roman digit : %c",roman_Number[i]);

return 0;

}



if((strlen(roman_Number) -i) > 2){

if(digit(roman_Number[i]) < digit(roman_Number[i+2])){

printf("Invalid roman number");

return 0;

}

}



if(digit(roman_Number[i]) >= digit(roman_Number[i+1]))

number = number + digit(roman_Number[i]);

else{

number = number + (digit(roman_Number[i+1]) - digit(roman_Number[i]));

i++;

}

i++;

}
int number1= number;

// 2ND NUMBER
printf("Enter SECOND roman number (Valid digits are I, V, X, L, C, D, M): \n");

scanf("%s",roman_Number);



while(roman_Number[i]){



if(digit(roman_Number[i]) < 0){

printf("Invalid roman digit : %c",roman_Number[i]);

return 0;

}



if((strlen(roman_Number) -i) > 2){

if(digit(roman_Number[i]) < digit(roman_Number[i+2])){

printf("Invalid roman number");

return 0;

}

}



if(digit(roman_Number[i]) >= digit(roman_Number[i+1]))

number = number + digit(roman_Number[i]);

else{

number = number + (digit(roman_Number[i+1]) - digit(roman_Number[i]));

i++;

}

i++;

}
int number2= number;
int answer = number1+number2;
printf("Its answer value is : ");
decimal2roman(answer);


return 0;



}



int digit(char c){



int value=0;



switch(c){

case 'I': value = 1; break;

case 'V': value = 5; break;

case 'X': value = 10; break;

case 'L': value = 50; break;

case 'C': value = 100; break;

case 'D': value = 500; break;

case 'M': value = 1000; break;

case '\0': value = 0; break;

default: value = -1;

}



return value;

}


//Made this code that makes roman number addition, i want to put an if statement that "The numbers in the range from 1 to 1999."

// My code needs to make XLV + LIV = XCIX but instead the results it gives is XC only.

[tpb]

11th post and still no code tags: http://www.cplusplus.com/forum/articles/16853/