20.47. Write a program that read any hexadecimal number and display equivalent decimal number.

#include<stdio.h>
#include<conio.h> 

#include<string.h>
void main ()
{
char *st;
int i,n,l;
clrscr();

st=(char *)malloc(sizeof(char)*100);
printf ("Enter any Hexadecimal number: ");

scanf("%s",st);

n=0;
l=strlen(st);
for(i=0; i<1; i++)

if(*st[i]>='0' && *st[i]<='9'

n=n*16+st[i]-48;

else if(*st[i]>='A' && *st[i]<='F'

n=n*16+st[i]-55;

else if(*st[i]>='a' && *st[i]<='f'

n=n*16+*st[i]-87;

printf("Eqivalent decimal number is: %ld",n);

getch ();

}