Java Programs Library

Convert int to binary

public class {

public static void convertBinary(int num){
int binary[] = new int[40];
int index = 0;
while(num > 0) {
binary[index++] = num%2;
num = num/2;
}

for(int i = index-1;i >= 0;i--) {
System.out.print(binary[i]);
}
}


public static void main(String[] args) {
convertBinary(45);
}

}

Below example shows how to convert string format of a number to number without calling Integer.parseInt() method. We can do this by converting each character into ascii format and form the number.

public class StringToNumber {

public static int convert_String_To_Number(String num){

char[] ch=num.toCharArray();
int sum=0;
int zeroAscii=(int) '0';

for(char c:ch) {
int tempAscii=(int) c;
sum=(sum*10)+(tempAscii-zeroAscii);
}

return sum;
}



public static void main(String[] args) {
System.out.println("\"3256\" == "+convert_String_To_Number("3256"));
System.out.println("\"76289\" == "+convert_String_To_Number("76289"));
System.out.println("\"90087\" == "+convert_String_To_Number("90087"));
}
}