C Programming Code Examples
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C program to convert Hexadecimal to Decimal number system
/* C program to convert Hexadecimal to Decimal number system
Write a C program to input hexadecimal number from user and convert it to Decimal number system. How to convert from Hexadecimal number system to Decimal number system in C programming.
Hexadecimal number system
Hexadecimal number system is a base 16 number system. It uses 16 symbols to represent all number i.e. 0123456789ABCDEF
Decimal number system
Decimal number system is a base 10 number system. It uses 10 symbols to represent all numbers i.e. 0123456789
Input a hexadecimal number from user. Store it in some variable hex.
Initialize decimal = 0, digit = length_of_hexadecimal_digit - 1 and j = 0.
Run a loop for each hex digit. Which is the loop structure should look like for(j=0; hex[j]!='\0'; j++).
Inside the loop find the integer value of hex[j]. Store it in some variable say val.
Convert the hex to decimal using decimal = decimal + (val * 16 ^ digit). Where val = hex[j]. */
#include <stdio.h>
#include <math.h>
#include <string.h>
int main()
{
char hex[17];
long long decimal, place;
int j = 0, val, len;
decimal = 0;
place = 1;
/* Input hexadecimal number from user */
printf("Enter any hexadecimal number: ");
gets(hex);
/* Find the length of total number of hex digit */
len = strlen(hex);
len--;
/* Iterate over each hex digit */
for(j=0; hex[j]!='\0'; j++)
{
/* Find the decimal representation of hex[j] */
if(hex[j]>='0' && hex[j]<='9')
{
val = hex[j] - 48;
}
else if(hex[j]>='a' && hex[j]<='f')
{
val = hex[j] - 97 + 10;
}
else if(hex[j]>='A' && hex[j]<='F')
{
val = hex[j] - 65 + 10;
}
decimal += val * pow(16, len);
len--;
}
printf("Hexadecimal number = %s\n", hex);
printf("Decimal number = %lld", decimal);
return 0;
}
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