Find element in a vector using a linear search
#include <iostream>
#include <vector>
#include <cstdlib>
#include <ctime>
using namespace std;
int linear_search(vector<int> v, int a){
for (int i = 0; i < v.size(); i++){
if (v[i] == a)
return i;
}
return -1;
}
void print(vector<int> a){
for (int i = 0; i < a.size(); i++)
cout << a[i] << " ";
cout << "\n";
}
void rand_seed(){
int seed = static_cast<int>(time(0));
srand(seed);
}
int rand_int(int a, int b){
return a + rand() % (b - a + 1);
}
int main()
{
rand_seed();
vector<int> v(20);
for (int i = 0; i < v.size(); i++)
v[i] = rand_int(1, 100);
print(v);
cout << "Enter number to search for: ";
int n;
cin >> n;
int j = linear_search(v, n);
cout << "Found in position " << j << "\n";
return 0;
}Returns all values within a range
#include <iostream>
#include <vector>
using namespace std;
vector<double> between(vector<double> v,
double low, double high)
{
vector<double> result;
for (int i = 0; i < v.size(); i++)
if (low <= v[i] && v[i] <= high)
result.push_back(v[i]);
return result;
}
int main()
{
vector<double> salaries(5);
salaries[0] = 35.0;
salaries[1] = 63.0;
salaries[2] = 48.0;
salaries[3] = 78.0;
salaries[4] = 51.0;
vector<double> midrange_salaries = between(salaries, 45.0, 65.0);
for (int i = 0; i < midrange_salaries.size(); i++)
cout << midrange_salaries[i] << "\n";
return 0;
}Use indexer to update element in the vector
#include <iostream>
using std::cout;
using std::endl;
#include <vector> // vector class-template definition
#include <algorithm> // copy algorithm
#include <iterator> // ostream_iterator iterator
#include <stdexcept> // out_of_range exception
int main()
{
int array[ 6 ] = { 1, 2, 3, 4, 5, 6 };
std::vector< int > integers( array, array + 6 );
std::ostream_iterator< int > output( cout, " " );
integers.push_back( 2 );
integers.push_back( 3 );
integers.push_back( 4 );
cout << "Vector integers contains: ";
std::copy( integers.begin(), integers.end(), output );
integers[ 0 ] = 7; // set first element to 7
cout << "\n\nVector integers contains: ";
std::copy( integers.begin(), integers.end(), output );
return 0;
}Vector integers contains: 1 2 3 4 5 6 2 3 4
Vector integers contains: 7 2 3 4 5 6 2 3 4
Use toupper function to convert all elements in a char vector to upper case
#include <iostream>
#include <vector>
#include <cctype>
using namespace std;
int main()
{
vector<char> v(10); // create a vector of length 10
cout << "Size = " << v.size() << endl;
for(int i=0; i<10; i++)
v[i] = i + "a";
cout << "Current Contents:\n";
for(int i=0; i<v.size(); i++) cout << v[i] << " ";
cout << "\n\n";
for(int i=0; i<v.size(); i++)
v[i] = toupper(v[i]);
cout << "Modified Contents:\n";
for(int i=0; i<v.size(); i++)
cout << v[i] << " ";
cout << endl;
return 0;
}Size = 10
Current Contents:
a b c d e f g h i j
Modified Contents:
A B C D E F G H I J
