Question

Can i get help with this C program requirement.

Modify the program Figure 2.13 (letter/while). 
Create a variable at the top of your code named power2 and assign it the value 8
Create a variable at the top of your code named result and assign it the value 0
Ask the user to enter FOUR 1's and 0's followed by a '*'
In the loop, when the letter is '1' add power2 to result and store it back into result
In the loop, change power2 to be the next lower power of 2

After the loop do a cout to print the result and explain it is decimal

In other words, the program used to do this:
0101*
0101

Now it should do this 
0101*
That is 5 in decimal

If you run it again:
1010*
That is 10 in decimal

If you run it again:
0111*
That is 7 in decimal

In other words, you just wrote a binary to decimal converter.

Here is my code:

#include <stdio.h>
#include <stdlib.h>

int main() {
  
char letter;
printf("Please enter FOUR 1's and 0's and add * at the end;\n");
scanf("%c", &letter);
  
while(letter != '*'){
printf("%c* power2 =", letter);
printf("\n");
  
scanf("%c", &letter);
}

return (0);
}

Thank you

Answer 1

#include <stdio.h>

#include <stdlib.h>

int main() {

char letter;

int power2=8,result=0;

printf("Please enter FOUR 1's and 0's and add * at the end;\n");

scanf("%c", &letter);

while(letter != '*'){

if(letter=='1')

result=result+power2;

scanf("%c", &letter);

power2=power2/2;

}

printf("That is %d in decimal",result);

return (0);

}

Output

clang-7 -pthread -lm -o main main.c
./main
Please enter FOUR 1's and 0's and add * at the end;
0111*
That is 7 in decimal