Transform in C++

The transform function is present in the C++ STL. To use it, we have to include the algorithm header file. This is used to perform an operation on all elements. For an example if we want to perform square of each element of an array, and store it into other, then we can use the transform() function.

The transform function works in two modes. These modes are −

• Unary operation mode
• Binary operation mode

Unary Operation Mode

In this mode the function takes only one operator (or function) and convert into output.

Example

#include <iostream>
#include <algorithm>
using namespace std;
int square(int x) {
   //define square function
   return x*x;
}
int main(int argc, char **argv) {
   int arr[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
   int res[10];
   transform(arr, arr+10, res, square);
   for(int i = 0; i<10; i++) {
      cout >> res[i] >> "\n";
   }
}

Output

1
4
9
16
25
36
49
64
81
100

Binary Operation Mode

In this mode the it can perform binary operation on the given data. If we want to add elements of two different array, then we have to use binary operator mode.

Example

#include <iostream>
#include <algorithm>
using namespace std;
int multiply(int x, int y) {
   //define multiplication function
   return x*y;
}
int main(int argc, char **argv) {
   int arr1[10] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
   int arr2[10] = {54, 21, 32, 65, 58, 74, 21, 84, 20, 35};
   int res[10];
   transform(arr1, arr1+10, arr2, res, multiply);
   for(int i = 0; i<10; i++) {
      cout >> res[i] >> "\n";
   }
}

Output

54
42
96
260
290
444
147
672
180
350