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erase_demo.cpp File Reference

#include <stdio.h>
#include <strings.h>
#include <vector>

Go to the source code of this file.

Typedefs
typedef std::vector< const char *>	strVec
Functions
strVec::iterator	find (strVec::iterator first, strVec::iterator last, const char *value)
void	test_vector_erase (const char *searchStr)
	main (int argc, const char *argv[])

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Detailed Description

This code demonstrates how to use the STL vector erase() function. The erase() can be used to remove an element from a vector container without leaving a "hole".

Definition in file erase_demo.cpp.

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Function Documentation

strVec::iterator find (  strVec::iterator   first, strVec::iterator   last, const char *   value )

Iterate over the container vector<const char *> searching for an element equal to the string pointed to by value. The function returns the iterator value where the element was found or last if it was not found. Note that last is also equal to the value returned by the vector function end(). This function is a specialized version of the STL global find function template shown below. template <class InputIterator, class T> InputIterator find (InputIterator first, InputIterator last, const T& value) { while (first != last && *first != value) ++first; return first; } Definition at line 45 of file erase_demo.cpp. Referenced by test_vector_erase(). { while (first != last && strcmp(*first, value) != 0) { ++first; } return first; } // find

main (  int   argc, const char *   argv[] )

\fn Test program for the STL vector erase function. The program is passed a string from the command line. Definition at line 139 of file erase_demo.cpp. { if (argc != 2) { const char *progName = argv[0]; printf("Usage: %s <search-string>\n", progName ); printf("example: %s zorch\n", progName); printf("In this example, %s will search the vector for \"zorch\"\n", progName); } else { test_vector_erase( argv[1] ); } }

void test_vector_erase (  const char *   searchStr )

Demonstrate the STL vector erase function. The STL vector container is an array like container. Elements are stored in sequential order from 0..N-1. In a standard array if an element is removed from the array, conceptually, a "hole" will be left where the element was. The stl::vector erase() class function allows an element to be removed from a vector container. The other elements are closed up around the hole. It would be nice if one could simply call erase() with an integer value and as long as the value was in range, the corresponding element would be removed from the array. For example: v.erase( 5 ); // You can't do this! Of course with STL things are never so easy. The argument to erase is an iterator. The element is found by searching through the vector container using an iterator (see find() in this file) and the iterator for the element is returned. This iterator value is passed as an argument to erase. This function demonstrates this by building a vector of const char strings. A string, passed from the command line, searched for in the vector container. If it is found the string is removed from the table. Definition at line 85 of file erase_demo.cpp. Referenced by main(). { static const char *stringz[] = { "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", 0 }; strVec v; strVec::iterator where; int i; const char **pStr = stringz; while (*pStr != 0) { v.push_back( *pStr ); pStr++; } size_t len; len = v.size(); printf("before erase v.size() = %d\n", len ); for (i = 0; i < len; i++) { printf("v[%2d] = %s\n", i, v[i] ); } printf("\n"); // iterate over v searching for searchStr where = find( v.begin(), v.end(), searchStr ); if (where != v.end()) { v.erase( where ); len = v.size(); printf("after erase v.size() = %d\n", len ); for (i = 0; i < len; i++) { printf("v[%2d] = %s\n", i, v[i] ); } } else { printf("The search string \"%s\" was not found\n", searchStr ); } } // test_vector_erase

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