Question

C CODE PLZ! Need all TO DO sections finished thanks

#include <stdio.h>


int main(int argc, char **argv) {
  const int BUF_LEN = 128;
  char str[BUF_LEN];
  int i;
  char c;
  int is_binary;
  int d, n;

  /* Get the user to enter a string */
  printf("Please enter a string made of 0s and 1s, finishing the entry by pressing Enter.\n");
  for (i=0; i<BUF_LEN-1; i++) {
    scanf("%c", &c);
    if (c == '\n') {
      break;
    }
    str[i] = c;
  } 
  str[i] = '\0';

  /* Check if the user string contains nothing but 0s and 1s */
  is_binary = 1;

  /* TODO */
  
  /* Proceed only of the string contains only 0s and 1s */
  if (is_binary) {
    /* Convert the string of 0s and 1s to an integer number n */
    n = 0;

    /* TODO */

    printf("The binary number %s is %d in decimal.\n", str, n);
  } else {
    printf("The string you entered, \"%s\", contains characters other than 0 and 1.\n", str);
  }

  return 0;
}

Answer 1

//header files
#include <stdio.h>
//included this header file as pow function is in this header files
#import <math.h>
//main function
int main(int argc, char **argv) {
    //string length
  const int BUF_LEN = 128;
  //array of characters str having capacity of BUF_LEN
  char str[BUF_LEN];
  //declaring variables
  int i;
  char c;
  int is_binary;
  int d, n;

  /* Get the user to enter a string */
  printf("Please enter a string made of 0s and 1s, finishing the entry by pressing Enter.\n");
  for (i=0; i<BUF_LEN-1; i++) {
    scanf("%c", &c);
    if (c == '\n') {
      break;
    }
    str[i] = c;
  }
  str[i] = '\0';

  /* Check if the user string contains nothing but 0s and 1s */
  is_binary = 1;

  /* TODO */
//i is the number of characters in character array
//j going 0 to i-1
  for(int j=0;j<i;j++)
  {
      //if the character at index j is neither 0 nor 1
      if(str[j]!='0' && str[j]!='1')
        {   //set is_binary to 0 which indicates that the string does not represent binary number
            is_binary=0;
            //go out of the loop
            break;
        }

  }//loop ends

  /* Proceed only of the string contains only 0s and 1s */
  //if is_binary is 1
  if (is_binary) {
    /* Convert the string of 0s and 1s to an integer number n */
    n = 0;

    /* TODO */
    //set d to 0 which points to the position of the first bits from the right side
     d=0;
    //j going from i-1 to 0 that means converting bits(from right side) to decimal and adding the results
    for(int j=i-1;j>=0;j--)
    {
        //use this formula
        //pow(2,d) which is 2 to the power d
        //(int) will convert the character(either 0 or 1) to its ASCII value(integer)
        //ASCII value of 1 is 49 and for 0 is 48 so here i am subtracting 48 from the ASCII value to get the real bit value
        //1-0=1 that is 49-48=1
        //0-0=0 that is 48-48 =0
        //((int)str[j]-48) means the bit value at index j
       n=n+pow(2,d)*((int)str[j]-48);
        //incrementing position
        d++;
    }
    //printing the decimal value
    printf("The binary number %s is %d in decimal.\n", str, n);
  }
  //if is_binary is 0
  else {
    //print this message
    printf("The string you entered, \"%s\", contains characters other than 0 and 1.\n", str);
  }

  return 0;
}
//main ends