94 lines
1.6 KiB
C++
94 lines
1.6 KiB
C++
//String.cc
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#include "String.hh"
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#include <iostream>
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String operator+( const String& lhs, const String& rhs ) {
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String result(lhs); // Copy lhs into res with constructor
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result += rhs ; // Use operator+= function which is a member of the class
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return result ;
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}
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String& String::operator=( const String& a ) {
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if ( &a != this ) {
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insert(a._s) ;
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}
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return *this ;
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}
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String& String::operator+=( const String& a ) {
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int newlen = _len + a._len ;
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char * newstr = new char[ newlen+1 ] ;
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strcpy(newstr, _s) ;
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strcpy(newstr + _len, a._s) ;
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if (_s) delete[] _s ;
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_s = newstr ;
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_len = newlen ;
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return *this ;
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}
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String& String::subString( int start, int stop ) {
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/*
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* Return a substring
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*
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* if stop is negative, interpret as len - stop
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* if start is negative, set start = 0
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*
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* if start > stop, return reversed string
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*/
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bool reverse = 0;
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int len = 0;
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char * tmp;
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// Higher than Range
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if ( start > _len ) {
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start = _len ;
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}
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if ( stop > _len ) {
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stop = _len ;
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}
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// Lower than Range
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if ( start < 0 ) {
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start = _len + start%_len ;
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}
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if ( stop < 0 ) {
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stop = _len + stop%_len ;
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}
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// Set length
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len = stop - start;
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if ( start > stop ) {
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// Make sure len is positive
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len = -1 * len ;
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reverse = 1;
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}
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// allocate
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tmp = new char[ len - 1];
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tmp[len] = '\0';
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for ( int i = 0 ; i < len ; i++ )
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{
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if ( reverse )
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{
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tmp[i] = _s[ start - i ];
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}
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else
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{
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tmp[i] = _s[ start + i ];
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}
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}
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// make it a String again
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String * result = new String(tmp);
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delete tmp;
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return *result;
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}
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