Mega Code Archive
Use subscript to change the value in a map
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#include <iostream>
using std::cout;
using std::endl;
#include <map> // map class-template definition
int main()
{
std::map< int, double, std::less< int > > pairs;
pairs.insert( std::map< int, double, std::less< int > >::value_type( 15, 2.7 ) );
pairs.insert( std::map< int, double, std::less< int > >::value_type( 30, 111.11 ) );
pairs.insert( std::map< int, double, std::less< int > >::value_type( 0, 1010.1 ) );
pairs.insert( std::map< int, double, std::less< int > >::value_type( 10, 22.22 ) );
pairs.insert( std::map< int, double, std::less< int > >::value_type( 25, 33.333 ) );
pairs.insert( std::map< int, double, std::less< int > >::value_type( 0, 77.54 ) ); // dup ignored
pairs.insert( std::map< int, double, std::less< int > >::value_type( 20, 9.345 ) );
pairs.insert( std::map< int, double, std::less< int > >::value_type( 15, 99.3 ) ); // dup ignored
cout << "pairs contains:\nKey\tValue\n";
// use const_iterator to walk through elements of pairs
for ( std::map< int, double, std::less< int > >::const_iterator iter = pairs.begin();
iter != pairs.end(); ++iter )
cout << iter->first << '\t' << iter->second << '\n';
pairs[ 25 ] = 9999.99; // use subscripting to change value for key 25
cout << "\n\n\n";
// use const_iterator to walk through elements of pairs
for ( std::map< int, double, std::less< int > >::const_iterator iter = pairs.begin();
iter != pairs.end(); ++iter )
cout << iter->first << '\t' << iter->second << '\n';
cout << endl;
return 0;
}
/*
pairs contains:
Key Value
0 1010.1
10 22.22
15 2.7
20 9.345
25 33.333
30 111.11
0 1010.1
10 22.22
15 2.7
20 9.345
25 9999.99
30 111.11
*/
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