Implement string and set operations on the arrays.

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Copy a string

In C++, the individual characters in a string can be accessed but not assigned or modified.

The following program copies a string to another string:

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#include <iostream>
#include <string>
using namespace std;
int main()
{
  string src = "just a string"; // The string to be copied
  int lsrc = src.length(); // Length of the string
  string dst = ""; // Creating an empty string
  for (int i = 0; i < lsrc; i++ )
  {
    dst += src[i]; // Copying the string
  }
  cout << src << endl;
  cout << dst << endl;
  return 0;
}

String concatenation

Concatenation means appending a string to another string. The following program concatenates two strings and stores them to another string.

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#include <iostream>
#include <string>
using namespace std;
int main()
{
  string str1 = "just a"; // First string
  string str2 = " string"; // Second string
  string str3 = ""; // Creating an empty string to store the concatenation result 
  for (int i = 0; i < str1.length(); i++ )
  {
    str3 += str1[i]; // Appending the characters of str1 to str3
  }
  for (int j = 0; j < str2.length(); j++)
  {
    str3 += str2[j]; // Appending the characters of str2 to str3
  }
  cout << str1 << endl;
  cout << str2 << endl;
  cout << str3 << endl;
  return 0;
}

Search a string in an array of strings

The following program checks whether a string or character is present in a string element.

Sample array

p = {"25","55","888","9","30","45"}

Sample value 1 of to be searched

55

Sample output 1

55 is found at index 1

Sample value 2 of to be searched

50

Sample output 2

50 is NOT FOUND in the array
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#include <iostream>
#include <string>
using namespace std;
int main()
{
  string p[] = {"25","55","888","9","30","45"}; // The 1st string which we want to search
  int lp = sizeof(p) / sizeof(p[0]); // Storing length
  string r = "55"; // String to be searched
  int i = 0;
  int found = 0;
  while (i < lp) // Loop that iterates through the whole array
  { 
    if (r == p[i]) // Checks for the element
    { 
      cout << r << " is found at index " << i;
      found = 1;
    }
    i ++;
  }
  if (found == 0)
  {
    cout << r << " is NOT FOUND in the array";
  }
  return 0;
}

Reverse a string

The following program stores the reverse of a string to another string.

Sample string

"was it a car or a cat I saw"

Sample output

ORIGINAL string is: was it a car or a cat i saw
REVERSED string is: was i tac a ro rac a ti saw
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#include <iostream>
using namespace std;
int main()
{
  string p = "was it a car or a cat i saw"; // The string to be reversed
  cout << "Original string is: " << p << endl;
  int lp = p.length(); // Length of string p
  string q = " "; // Empty string to store the reverse
  int i = 1;
  int found = 0;
  while (i <= lp) // This loop will terminate when i is greater than lp
  { 
    q += p[lp - i]; // Reversing the string
    i++;
  }
  cout << "REVERSED string is: " << q;
  return 0;
}

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