题意：将一个字符串中所有的空格替换成指定的字符串。 思路：先遍历字符串，计算有多少空格，再计算将该字符串中空格替换了指定字符串后，替换后的长度是多大。初始化一个长度为替换后长度的数组，设定两个游标，index1指向替换后数组的末尾，index2指向替换前字符串的末尾，从后往前遍历，若index2指定的字符为空格，则在index1指定的位置加上待替换的字符串，否则则将字符复制至index1位置。 代码：
package MianShiTi_4;public class MianShiTi_4 { public static int countSpace(String newstring){ int count =0; for(int i = 0; i< newstring.length() ; i++){ if(newstring.charAt(i) == ' '){ count++; } } return count; } public static int calLength(String newstring) { int length = 0; int spaceCount = 0; spaceCount = countSpace(newstring); length = newstring.length() + spaceCount*2; return length; } public String replaceAllSpace(String newString){ String s1; int newlength = calLength(newString); int originalLength = newString.length(); char []tempArray = new char[newlength]; System.arraycopy(newString.toCharArray(), 0, tempArray, 0, newString.toCharArray().length); int indexOfString = originalLength - 1; int indexOfNewString = newlength - 1; while (indexOfString >=0 && indexOfString != indexOfNewString) { if(newString.charAt(indexOfString) == ' '){ tempArray[indexOfNewString--] = '0'; tempArray[indexOfNewString--] = '2'; tempArray[indexOfNewString--] = '%'; }else{ tempArray[indexOfNewString-- ] = tempArray[indexOfString]; } indexOfString --; } s1 =new String(tempArray); return s1; } public static void main(String[] args) { String string = "I am ok"; MianShiTi_4 test = new MianShiTi_4(); int count1 = test.countSpace(string); int count2 = test.calLength(string); String s2; s2 = test.replaceAllSpace(string); System.out.PRintln(s2); //System.out.println(count1+" "+count2); }}新闻热点
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