I'm looking to make a hex to octal convert in C, and right now I'm able to convert a string from hex to binary. Now I'm looking to convert it from binary to octal. I believe that this was the simplest way. This is what I have for now. It's a function being called in a main program. How do I go from now? I'm kind of stuck and any help would be great. Thanks in advance.
#include "my_lib_3.h"
#include <string.h>
#include "mrb_lib_1.h"
#include <math.h>
char *hex2octal(char s[]){
char input_string [20] = "";
//char return_string[50] = "";
int num, binary_val, decimal_val = 0, base = 1, rem;
printf("Enter a hex number:\n");
scanf("%s",input_string);
int i;
for (i=0; i<1; i++) {
switch(input_string[i]){
case '0' :
// strcat(return_string, "0000");
num = "0000";
break;
case '1' :
// strcat(return_string, "0001");
num = "0001";
break;
case '2' :
// strcat(return_string, "0010");
num = "0010";
break;
case '3':
// strcat(return_string, "0011");
num = "0011";
break;
case '4':
// strcat(return_string, "0100");
num = "0100";
break;
case '5':
// strcat(return_string, "0101");
num = "0101";
break;
case '6':
// strcat(return_string, "0110");
num = "0110";
break;
case '7':
// strcat(return_string, "0111");
num = "0111";
break;
case '8':
// strcat(return_string, "1000");
num = "1000";
break;
case '9':
// strcat(return_string, "1001");
num = "1001";
break;
case 'A':
// strcat(return_string, "1010");
num = "1010";
break;
case 'B':
// strcat(return_string, "1011");
num = "1011";
break;
case 'C':
// strcat(return_string, "1100");
num = "1100";
break;
case 'D':
// strcat(return_string, "1101");
num = "1101";
break;
case 'E':
// strcat(return_string, "1110");
num = "1110";
break;
case 'F':
// strcat(return_string, "1111");
num = "1111";
break;
default:
printf("Program doesn't support this yet\n");
break;
}
printf("The binary equivalent of %s is %s\n", input_string, num);
int z;
for (z = 0; return_string[z] != '\0'; z++) {
if(return_string[z] = '5'){
printf("%i",z);
printf("Yo!\n");
z++;
}
}
return 0;
}
char *octal2dec(char s[]){
}
You can convert HEX to Octal by using two ways :
Way 1 - Convert number into binary then convert binary into Octal
Way 2 - As I can see that your binary is in string ,
so do it like this :
1-Take a group of 3 binary code from right to left
2-Convert it into Octal
For example you have hex number as F5
now binary of this number is 1111 0101
to convert it in octal make a group of 3 from binary number as
11 110 101
and then convert each group into octal as
binary -- octal
101 -- 5
110 -- 6
011 -- 3
Therefore octal representation of your HEX number F5 is 365
Code to convert binary string to octal representation
int main{
char str[]="11110101"; //binary string
char temp[4]; //temp string
int j,i,length,flag=0,oct=0,num=0,t;
length=strlen(str); //length of the binary string
//printf("%d",length);
i=length-1; //last index of a binary string
while(i>=0){
j=2; // as we want to divide it into grp of 3
while(j>=0){
if(i>=0){
temp[j]=str[i--]; // take 3 characters in the temporary string
j--;
}
else{
flag=1; // if binary string length is not numtiple of 3
break;
}
}
if(flag==1){
while(j>=0){
temp[j]='0'; //add leading 0 if length is not multiple of 3
j--;
}
flag=0;
}
temp[3]='\0'; //add null character at the end of the tempory string
// use comparisons of tempory string with binary numbers
if(strcmp(temp,"000")==0){
oct=oct*10+0;
}
else if(strcmp(temp,"001")==0){
oct=oct*10+1;
}
else if(strcmp(temp,"010")==0){
oct=oct*10+2;
}
else if(strcmp(temp,"011")==0){
oct=oct*10+3;
}
else if(strcmp(temp,"100")==0){
oct=oct*10+4;
}
else if(strcmp(temp,"101")==0){
oct=oct*10+5;
}
else if(strcmp(temp,"110")==0){
oct=oct*10+6;
}
else if(strcmp(temp,"111")==0){
oct=oct*10+7;
}
// printf("\n%s",temp);
}
//as we move from last first character reverse the number
num=oct;
flag=0;
t=1;
while(num>0){
if(flag==0){
t=num%10;
flag=1;
}
else{
t=t*10+num%10;
}
num=num/10;
}
//print the octal number
printf("\n Octal number is : %d",t);
}