Hexadacimal To Decimal Program In C

Finding that a given number is even or odd, is a classic C program. We shall learn the use of conditional statement if-else in C.

Algorithm

Algorithm of this program is very easy −

START
      
   Step 1 → Take integer variable A
          
   Step 2 → Assign value to the variable

   Step 3 → Perform A modulo 2 and check result if output is 0
   
   Step 4 → If true print A is even
   
   Step 5 → If false print A is odd

STOP

Flow Diagram

We can draw a flow diagram for this program as given below −

Pseudocode

procedure even_odd()
   
   IF (number modulo 2) equals to 0
      PRINT number is even
   ELSE
      PRINT number is odd
   END IF

end procedure

Implementation

Implementation of this algorithm is given below −

#include <stdio.h>

int string_length(char s[])
{
	int i=0;

	while(s[i]!='\0')
		i++;
		
return i;	
}

int hexa2decimal(char n[])
{
	int i,decimal,mul=0;

	for(decimal=0,i=string_length(n)-1;i>=0;--i,mul+=4)
		if(n[i]>='0' && n[i]<='9')
			decimal+=(n[i]-48)*(1<<mul);
		else if(n[i]=='A')
			decimal+=10*(1<<mul);
		else if(n[i]=='B')
			decimal+=11*(1<<mul);
		else if(n[i]=='C')
			decimal+=12*(1<<mul);
		else if(n[i]=='D')
			decimal+=13*(1<<mul);
		else if(n[i]=='E')
			decimal+=14*(1<<mul);
		else if(n[i]=='F')
			decimal+=15*(1<mul);

	return decimal;
}

int main()
{
	char n[50];
	int i,decimal,mul=0;
	
	printf("Enter a hexa number :");
	scanf("%s",n);

	printf("Decimal equivalent is : %d",hexa2decimal(n));
return 0;
}

Output

Output of the program should be −

24 is even
31 is odd