Question

I need little help with C language. I need to pass what I get from HexToBin(char* hexdec) into char* input so that what I got there it should pass it as string array parametr.
Example:
Enter IEEE-Hex: 40200000
Equivalent Binary value is : 01000000001000000000000000000000
Decimal Number: 2.5

#include <stdio.h>

void HexToBin(char* hexdec)
{

   long int i = 0;

   while (hexdec[i]) {

       switch (hexdec[i]) {
       case '0':
           printf("0000");
           break;
       case '1':
           printf("0001");
           break;
       case '2':
           printf("0010");
           break;
       case '3':
           printf("0011");
           break;
       case '4':
           printf("0100");
           break;
       case '5':
           printf("0101");
           break;
       case '6':
           printf("0110");
           break;
       case '7':
           printf("0111");
           break;
       case '8':
           printf("1000");
           break;
       case '9':
           printf("1001");
           break;
       case 'A':
       case 'a':
           printf("1010");
           break;
       case 'B':
       case 'b':
           printf("1011");
           break;
       case 'C':
       case 'c':
           printf("1100");
           break;
       case 'D':
       case 'd':
           printf("1101");
           break;
       case 'E':
       case 'e':
           printf("1110");
           break;
       case 'F':
       case 'f':
           printf("1111");
           break;
       default:
           printf("\nInvalid hexadecimal digit %c",
               hexdec[i]);
       }
       i++;
   }
}

union {
int i;
float f;
} myunion;

int binstr2int(char *s)
{
int rc;
for (rc = 0; '\0' != *s; s++) {
if ('1' == *s) {
rc = (rc * 2) + 1;
} else if ('0' == *s) {
rc *= 2;
}
}
return rc;
}

int main(void) {
printf("\nEnter IEEE-Hex: ")
char hexdec[100];
   scanf("%s", &hexdec);
   printf("\nEquivalent Binary value is : ");
   HexToBin(hexdec); // this is printing Binary numbers

// I need to pass HexToBin() into char* input so that it will contain binary string array;

char * input = // if you will put here something like "111100001111"// it will give you decimal numbers // I want to pass here what I get from HexToBin(hexdec) and it should be in string array;
float *output;

int converted = binstr2int(input);

output = (float*)&converted; //
printf("\nDecimal Number: %f\n", *output); // this is what printing decimal number numbers
}

Answer 1

/********************************main.c****************/

#include <stdio.h>
#include <string.h>
char* HexToBin(char* hexdec)
{

long int i = 0;
char binayString[100] = "";
while (hexdec[i]!='\0') {

switch (hexdec[i]) {
case '0':
strcat(binayString, "0000");
break;
case '1':
strcat(binayString, "0001");
break;
case '2':
strcat(binayString, "0010");
break;
case '3':
strcat(binayString, "0011");
break;
case '4':
strcat(binayString, "0100");
break;
case '5':
strcat(binayString, "0101");
break;
case '6':
strcat(binayString, "0110");
break;
case '7':
strcat(binayString, "0111");
break;
case '8':
strcat(binayString, "1000");
break;
case '9':
strcat(binayString, "1001");
break;
case 'A':
case 'a':
strcat(binayString, "1010");
break;
case 'B':
case 'b':
strcat(binayString, "1011");
break;
case 'C':
case 'c':
strcat(binayString, "1100");;
break;
case 'D':
case 'd':
strcat(binayString, "1101");
break;
case 'E':
case 'e':
strcat(binayString, "1110");
break;
case 'F':
case 'f':
strcat(binayString, "1111");
break;
default:
printf("\nInvalid hexadecimal digit %c",
hexdec[i]);
}
i++;
}
printf("%s ",binayString);
return binayString;
}

union {
int i;
float f;
} myunion;

int binstr2int(char* s)
{
int rc;
for (rc = 0; '\0' != *s; s++) {
if ('1' == *s) {
rc = (rc * 2) + 1;
} else if ('0' == *s) {
rc *= 2;
}
}
return rc;
}

int main(void) {
   printf("\nEnter IEEE-Hex: ");
   char hexdec[100];
    scanf("%s", &hexdec);
    printf("\nEquivalent Binary value is: ");
// this is printing Binary numbers
  
// I need to pass HexToBin() into char* input so that it will contain binary string array;

char * input = HexToBin(hexdec);// if you will put here something like "111100001111"// it will give you decimal numbers // I want to pass here what I get from HexToBin(hexdec) and it should be in string array;
float *output;

int converted = binstr2int(input);

output = (float*)&converted; //
printf("\nDecimal Number: %f\n", *output); // this is what printing decimal number numbers
}

/**********************output******************/

Enter IEEE-Hex: 40200000

Equivalent Binary value is: 01000000001000000000000000000000
Decimal Number: 2.500000

--------------------------------

Please let me know if you have any doubt or modify the answer, Thanks:)