顺序串

public class SqString {

char[] data;
int length;

SqString() {
data = new char[30];
length = 0;
}

SqString(String s) {
data = new char[30];
for(int i=0; i<s.length(); i++) {
data[i] = s.charAt(i);

}
length = s.length();
}

void strCopy(SqString s) {
for(int i=0; i<s.length; i++) {
data[i] = s.data[i];
}
length = s.length;
}

boolean strEqual(SqString s) {
if(length != s.length)
return false;
for(int i=0; i<length; i++) {
if(data[i] != s.data[i]) {
return false;
}
}
return true;
}

int strLen() {
return length;
}

void strConcat(SqString s) {
for(int i=0; i<s.length; i++) {
data[i+length] = s.data[i];
}
length = length + s.length;
}

SqString subStr(int from, int to) {
SqString s = new SqString();
if(from<0 || from >=length || from+1>to || to<=0 || to>length) {
return s;
}
for(int i= from ; i<to; i++) {
s.data[i-from] = data[i];
}
s.length = to - from;
return s;
}

void strInsert(int from, SqString s) {
if(from <0 || from > length) {
return;
}
for(int i=length-1 ; i>=from; i--) {
data[i+s.length] = data[i];
}
for(int i=0; i<s.length; i++) {
data[i+from] = s.data[i];
}
length += s.length;
}

SqString strDel(int from, int to) {
SqString s = new SqString();
if(from<0 || from >=length || from+1>to || to<=0 || to>length) {
return s;
}

for(int i=from ; i<to; i++) {
s.data[i-from] = data[i];
}
s.length = to - from;
for(int i=to; i<length; i++) {
data[i - to + from] = data[i];
}
length -= (to-from);
return s;
}

void strReplace(SqString s, int from, int to) {
strDel(from, to);
strInsert(from, s);
}

void display() {
for(int i=0; i<length; i++) {
System.out.print(data[i]);

}
System.out.println();
}

int strCmp(SqString s) {
int len;
if(length < s.length)
len = length;
else
len = s.length;
for(int i=0; i<len; i++) {
if(data[i] < s.data[i])
return -1;
else if(data[i] > s.data[i])
return 1;
}
if(length == s.length)
return 0;
else if(length < s.length) {
return -1;
} else {
return 1;
}
}
public static void main(String[] args) {
SqString s = new SqString("Hello");
s.display();
s.strCopy(new SqString(" World!"));
s.display();
System.out.println(s.strEqual(new SqString(" World!")));
System.out.println(s.strLen());
s.strConcat(new SqString("Hello"));
s.display();
SqString res = s.subStr(4, 12);
res.display();
s.display();
s.strInsert(2, new SqString("qq"));
s.display();
s.strInsert(14, new SqString("haha"));
System.out.println(s.strLen());
s.display();
res = s.strDel(3, 8);
s.display();
res = s.strDel(9, 13);
s.display();
s.strReplace(new SqString("Tencent"), 2, 4);
s.display();
System.out.println(s.strLen());
System.out.println(s.strCmp(new SqString(" WTencentHello")));
System.out.println(s.strCmp(new SqString(" WTencent")));
System.out.println(s.strCmp(new SqString(" WTencentHello4554")));
System.out.println(s.strCmp(new SqString(" Wt")));

}

}

Hello
World!
true
7
World!Hello
ld!Hello
World!Hello
Wqqorld!Hello
18
Wqqorld!Hellohaha
Wq!Hellohaha
Wq!Hello
WTencentHello
14
0
1
-1
-1