﻿ Convert decimal number to binary string ~ Programming Tutorials by SourceTricks
Wednesday, July 11, 2012

## Convert decimal number to binary string

### Write a program to convert decimal number to binary string

The approach:-
1. Initialize a string array to hold the output binary string.

2. mod the input number by 2.  If reminder is '1' include '1' in the output string. Else include '0'.

3. Divide the number by 2 for next iteration.

4. Repeat steps 2 and 3 till number becomes 0.

5. Reverse the string to get the output sequence.

#### C++ program to convert decimal number to binary string

```#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cmath>
using namespace std;

char* dec2bin(int n) {
char* str = (char*)malloc(sizeof(32));
char bin_str[] = { '0', '1' };

int count = 0;
while ( n > 0 ) {
int rem = n % 2;
n = n / 2;
rem ? str[count] = bin_str[1] : str[count] = bin_str[0];
count++;
}
str[count] = '\0';

// reverse the string
int size = strlen(str) - 1;
for ( int i = 0; i <= size/2; i++ ) {
char ch = str[i];
str[i] = str[size - i];
str[size - i] = ch;
}

return str;
}

int main() {
int n = 100;
cout << dec2bin(n) << endl;
}```

Output:-
`1100100`

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