Convert String (binary) to Integer

Question

I am writing a program where the input data (in binary) is split into half and convert to integer to perform some calculation. So I:

Accept binary input and store as "String"

Split string (note: to be treated as binary) into half and convert to int and store in x and y

So far i have written step 1.

int main() {
    string input;
    cout << "Enter data:";
    getline(cin, input);

    int n = input.size();
    int n1 = n/2;

    string a, b;
    a = input.substr(0,n1);
    b = input.substr(n1);

    cout << "a: " << a;
    cout << "b: " << b;
}

Would like to know how to achieve step 2. Thanks in advance.

@Nolane How is your comment relevant? Question was about binary format, while atoi "[...] takes an optional initial plus or minus sign followed by as many base-10 digits [...]". As to the question - we don't solve homeworks here. Read this: en.wikipedia.org/wiki/Binary_number#Decimal and then implement. It is one of the most basic algorithms in CS. — Mateusz Grzejek
– Mateusz Grzejek, Commented Jul 26, 2015 at 17:28
Homework related questions are fine as long as you're not simply asking us to complete a step for you. Just re-factor your question to ask more specifically what about step 2 your having problems with and make sure you include things you've tried so far. — Dan Beaulieu
– Dan Beaulieu, Commented Jul 26, 2015 at 18:11
@DanBeaulieu this is not homework. i am just trying out something and yes i will do this on my own. In no way asking anyone to provide the complete code easily to me. — user4914916
– user4914916, Commented Jul 26, 2015 at 18:15
@MateuszGrzejek Thanks for the link. I'm trying to implement. — user4914916
– user4914916, Commented Jul 26, 2015 at 18:16

Christophe · Accepted Answer · 2015-07-26 18:22:11Z

2

You can try this:

if(a.length() <= sizeof(unsigned int) * 8) {
    unsigned x = 0; 
    for(int i = 0; i < a.length(); i++) {
        x <<= 1;  // shift byt 1 to the right
        if(a[i] == '1')
            x |= 1; // set the bit
        else if(a[i] != '0') {
            cout << "Attention: Invalid input: " << a[i] << endl; 
            break; 
        }
    }
    cout << "Result is " << x << endl; 
}
else cout << "Input too long for an int" << endl;

It uses

shift left <<, to move the binary bits, when you go right in the ascii string;
binary or | for setting the bits.

edited Jul 26, 2015 at 18:22

answered Jul 26, 2015 at 18:17

Christophe

75.1k7 gold badges87 silver badges182 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Archit Garg · Accepted Answer · 2015-07-27 16:23:11Z

0

int bin2dec(char* str) {
 int n = 0;
 int size = strlen(str) - 1;
        int count = 0;
 while ( *str != '\0' ) {
  if ( *str == '1' ) 
      n = n + pow(2, size - count );
  count++; 
  str++;
 }
 return n;
}

int main() {
 char* bin_str = "1100100";
 cout << bin2dec(bin_str) << endl;
}

answered Jul 27, 2015 at 16:23

Archit Garg

1,0121 gold badge8 silver badges16 bronze badges

Collectives™ on Stack Overflow

Convert String (binary) to Integer

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related