#include

int get_value(char c) {

switch (c) {

case 'I': return 1;

case 'V': return 5;

case 'X': return 10;

case 'L': return 50;

case 'C': return 100;

case 'D': return 500;

case 'M': return 1000;

default: return -1;

}

}

int roman_to_decimal(char *roman) {

int decimal = 0;

int prev = 0;

for (int i = 0; roman[i] != '\0'; i++) {

int current = get_value(roman[i]);

if (current == -1) {

return -1;

}

if (current > prev) {

decimal += current - 2 * prev;

} else {

decimal += current;

}

prev = current;

}

return decimal;

}

int main() {

char roman[100];

int decimal;

printf("Enter a Roman numeral: ");

scanf("%s", roman);

decimal = roman_to_decimal(roman);

if (decimal == -1) {

printf("Invalid Roman numeral ");

} else {

printf("Decimal equivalent: %d ", decimal);

}

return 0;

}

/////

#include

int roman_to_decimal(char *roman) {

int decimal = 0;

int prev = 0;

for (int i = 0; roman[i] != '\0'; i++) {

int current = 0;

switch (roman[i]) {

case 'I': current = 1; break;

case 'V': current = 5; break;

case 'X': current = 10; break;

case 'L': current = 50; break;

case 'C': current = 100; break;

case 'D': current = 500; break;

case 'M': current = 1000; break;

default: return -1;

}

if (current > prev) {

decimal += current - 2 * prev;

} else {

decimal += current;

}

prev = current;

}

return decimal;

}

int main() {

char roman[100];

int decimal;

printf("Enter a Roman numeral: ");

scanf("%s", roman);

decimal = roman_to_decimal(roman);

if (decimal == -1) {

printf("Invalid Roman numeral ");

} else {

printf("Decimal equivalent: %d ", decimal);

}

return 0;

}