ME3 Alternative

#include <stdio.h>#include <stdlib.h>int main(){	int value;    int flag = 0;	char character;	int total = 0;while (1){	character = getchar();	while(character != '\n'){		if((character >= 'A') && (character <= 'F'))			value = character - 'A' + 10;		if((character >= 'a') && (character <= 'f'))			value = character - 'a' + 10;		if((character >= '0') && (character <= '9'))			value = character - '0';		if(((character > '9') && (character < 'A'))||((character > 'F') && (character < 'a'))||character > 'f')   		     {flag=1;                      break;} //turns on flag for inputs not hex             		total = total * 16 + value;		character = getchar();	}			if (flag!=1)          	printf("%d\n", total);	else	{        printf("Invalid input");        break;        };		total = 0;	}    system("pause");	return 0;}