Merge two strings letter by letter in Java?

Question

Given two strings, A and B, create a bigger string made of the first char of A, the first char of B, the second char of A, the second char of B, and so on. Any le

Answer 1

You've got a workable approach, but you could significantly simplify it by using a single loop with two counters:

int apos = 0, bpos = 0;
while (apos != a.length() || bpos != b.length()) {
    if (apos < a.length()) m += a.charAt(apos++);
    if (bpos < b.length()) m += b.charAt(bpos++);
}

In this loop you will "make progress" on each step by advancing apos, bpos, or both. Once a string runs out of characters, its corresponding pos stops advancing. The loop is over when both pos reach their ends.

Note: When you need to append to a string in a loop, use StringBuilder.

Answer 2

public String mixString(String a, String b) {
  String c="";
  String left="";
  int min;
  if(a.length()>b.length()) {
      min=b.length();
     left=a.substring(b.length(),a.length());
  }
  else {
      min=a.length();
      left=b.substring(a.length(),b.length());
  }

  for(int i=0;i<min;i++) {
      c +=a.substring(i,i+1)+b.substring(i,i+1);

  }   
return c+left;            
}

Answer 3

Here is my attempt::

public static String mixString1(String a,String b){

    String result="";

    int startValue = 0;
    int increment = 0;

    if(a.length()<=b.length()){

    for(int i=0;i<a.length();i++){

            result =  result+a.charAt(i)+b.charAt(i);

    }

    }

    else if(a.length()>=b.length()){

        for(int i=0;i<b.length();i++){

                result =  result+a.charAt(i)+b.charAt(i);

        }

        }


    if(a.length()<b.length()){

        startValue= a.length();
        increment = b.length();

    }

    else {

        startValue= b.length();
        increment = a.length();

    }

    if(a.length()<b.length()){

    for(int j=startValue;j<increment;j++){

        result = result+b.charAt(j);

    }
    }
    else if(a.length()>b.length()){

        for(int j=startValue;j<increment;j++){

            result = result+a.charAt(j);

        }


    }

    return result;
    }

Answer 4

I used Merge sort approach to solve this problem. First I converted both the strings into their respective character arrays and then merged both the arrays and converted the array back to a string. You can find my code below,I have tested the code and it is working. Let me know if you have any questions..

public String merge(String leftStr, String rightStr) {  
        char[]left = leftStr.toCharArray();
        char[]right = rightStr.toCharArray();
        int nL = left.length;
        int nR= right.length;
        char[] mergeArr= new char[nL+nR];
        int i=0,j=0,k=0;
        int temp =0;
        while(i<nL && j<nR){

            if (temp==0){
                mergeArr[k]=left[i];
                i++;
                temp =1;
            }else{
                mergeArr[k]=right[j];
                j++;
                temp=0;
            }
            k++;            
        }
        while(i<nL){

            mergeArr[k]=left[i]; k++; i++;
        }
        while(j<nR){

            mergeArr[k]=right[j]; k++; j++;
        }


        return new String(mergeArr);

    }

Answer 5

Another approach using StringBuilder and char[]. Works as long as the first is longer than the second, which is guaranteed by the first method.

public String mixString(String a, String b) {
    if (b.length() > a.length())
        return mixString(new StringBuilder(b), a.toCharArray(), 0);
    return mixString(new StringBuilder(a), b.toCharArray(), 1);
}

public String mixString(StringBuilder ab, char[] b, int start) {
    int i = 0;
    for (char c : b)
        ab.insert(i++*2 + start, "" + c);
    return ab.toString();
}

Answer 6

public String mixString(String a, String b) {
StringBuilder sb = new StringBuilder("");
int longer = 0;
if (a.length()>b.length()) longer = a.length();
else longer = b.length();
for (int i = 0; i <longer;i++){
if (i<a.length()) sb.append(a.substring(i,i+1));
if (i<b.length()) sb.append(b.substring(i,i+1));
}
return sb.toString();
}