Write method to replace all spaces in a string with '%20'.

File1: StringRoutines.java
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package org.developersbrain.solutions;

public class StringRoutines {

/*Find and replace a sequence of characters*/
int getArrayLength(char[] arrList){
return arrList.length;
}

char[] replace(char[] arrList,int startPos,int endPos,char[] findChar,char[] repChar){
int findLength=getArrayLength(findChar);
int repLength=getArrayLength(repChar);
char[] chrRep = null;
if(findLength==repLength){
for(int i=startPos,k=0;i<endPos;i++,k++)
arrList[i]=repChar[k];
}else if(repLength>findLength){
int diff=(repLength-findLength);
int arrLength=getArrayLength(arrList);
chrRep=new char[arrLength+diff];
int i,j;
for(i=0,j=0;i<arrLength;j++,i++){
chrRep[j]=arrList[i];
if(j==startPos){
for(int k=0;k<repLength;k++,j++){
chrRep[j]=repChar[k];
}
j--;
i=(j-diff);
}
}
}else{
int diff=(findLength-repLength);
int arrLength=getArrayLength(arrList);
chrRep=new char[arrLength-diff];
int i,j;
for(i=0,j=0;i<arrLength;j++,i++){
chrRep[j]=arrList[i];
if(j==startPos){
for(int k=0;k<repLength;k++,j++){
chrRep[j]=repChar[k];
}
j--;
i=j+1;
}
}
}

if(chrRep==null) return arrList;
else return chrRep;

}

char[] replace(char[] arrList,char[] findChar,char[] repChar){
int arrLength = getArrayLength(arrList);
int findCharLength=getArrayLength(findChar);
int repCharLength=getArrayLength(repChar);
int i,j,k;


for(i=0;i<arrLength;i++){

for(j=i,k=0;k<findCharLength;j++,k++){
if(arrList[j]!=findChar[k]) break;
}
if(findCharLength==k){
arrList=replace(arrList,i,j,findChar,repChar);
if(findCharLength<repCharLength){
arrLength=arrLength+(repCharLength-findCharLength);
}else if(findCharLength>repCharLength){
arrLength=arrLength-(findCharLength-repCharLength);
//i=i-(findCharLength-repCharLength);
}
}
}
return arrList;
}

String convertArrString(char[] arrList){
int arrLength = getArrayLength(arrList);
String retString="";
for(int i=0;i<arrLength;i++){
retString=retString+arrList[i];
}
return retString;
}

public String replace(String inputString,String findStr,String replaceStr){
char[] arrList=inputString.toCharArray();
char[] findChar=findStr.toCharArray();
char[] repChar=replaceStr.toCharArray();
if(findChar.length==0 || repChar.length==0){
return inputString;
}else{
char[] outArr=replace(arrList,findChar,repChar);
return convertArrString(outArr);
}
}

}

File2: MainClass.java

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package org.developersbrain.solutions;

public class MainClass {

public static void main(String[] args){

StringRoutines sr=new StringRoutines();

String str="Hey find and replace me.find find find     .find";

String findStr=" ";

String repStr="%20";

System.out.println("Case 1:");

System.out.println("Given String:"+str);

System.out.println("Find text:"+findStr);

System.out.println("Replace with:"+repStr);

str=sr.replace(str, findStr, repStr);

System.out.println("Modified String: "+str);

   System.out.println();

str="Hey find and replace me.find find find     .find";

findStr="find";

repStr="FIND";

System.out.println("Case 2:");

System.out.println("Given String:"+str);

System.out.println("Find text:"+findStr);

System.out.println("Replace with:"+repStr);

str=sr.replace(str, findStr, repStr);

System.out.println("Modified String: "+str);

   System.out.println();

str="Hey find and replace me.find find find     .find";

findStr="find";

repStr="you     YOU";

System.out.println("Case 3:");

System.out.println("Given String:"+str);

System.out.println("Find text:"+findStr);

System.out.println("Replace with:"+repStr);

str=sr.replace(str, findStr, repStr);

System.out.println("Modified String: "+str);

}

}

Output:

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Case 1:

Given String:Hey find and replace me.find find find     .find

Find text: " " ---Space Character

Replace with:%20

Modified String: Hey%20find%20and%20replace%20me.find%20find%20find%20%20%20%20%20.find

Case 2:

Given String:Hey find and replace me.find find find     .find

Find text:find

Replace with:FIND

Modified String: Hey FIND and replace me.FIND FIND FIND     .FIND

Case 3:

Given String:Hey find and replace me.find find find     .find

Find text:find

Replace with:you     YOU

Modified String: Hey you     YOU and replace me.you     YOU you     YOU you     YOU     .you     YOU