{"post":"

In the previous chapters, we have read about both the topics of pointers as well as the functions in C++. But in this chapter, we are going to learn how these two concepts can be used with one another in C++. Both these topics are of utmost importance and are really fun to use. So let us take a look at them in detail.

Passing pointers to functions:

C++ allows the coder to pass a pointer to a function. To do so, simply declare the function parameter as a pointer type.

#include <iostream>\n#include <ctime>\n\nvoid gS(unsigned long* par); // function declaration\n\nint main()\n{\n    unsigned long sec;\n    gS(&sec);\n\n    // print the actual value\n    cout << \"Number of seconds: \" << sec << endl;\n\n    return 0;\n}\n\nvoid gS(unsigned long* par) // function definition\n{\n    // get the current number of seconds\n    *par = time(NULL);\n}\n\n

When the above code is compiled and executed, it produces the following result −

Number of seconds: 1294450\n

In the above example, we pass an unsigned long pointer to a function and change the value inside the function which reflects back in the calling function.

Return Pointers from Functions:

C++ also allows the feature to return pointers from the functions. For this purpose, we use the following

Syntax:

int *Func_name() {\n\n   .\n\n   .\n\n   .\n\n}\n

Note: Here we are returning an integer value because, pointers are actually addresses, which are actually numbers themselves.

#include <iostream>\n#include <ctime>\n\n// function to generate and return random numbers.\nint* getRandom()\n{\n    static int r[5];\n\n    // set the seed\n    srand((unsigned)time(NULL));\n\n    for (int i = 0; i < 5; ++i)\n    {\n        r[i] = rand();\n        cout << r[i] << endl;\n    }\n\n    return r;\n}\n\n// main function to call above defined function.\nint main()\n{\n    // a pointer to an int.\n    int* p;\n    p = getRandom();\n\n    for (int i = 0; i < 5; i++)\n    {\n        cout << \"*(p + \" << i << \") : \";\n        cout << *(p + i) << endl;\n    }\n\n    return 0;\n}\n\n

Output:

672723198\n\n9998735695\n\n804513585\n\n971235677\n\n618989504\n\n\n*(p + 0): 672723198\n\n*(p + 1): 9998735695\n\n*(p + 2): 804513585\n\n*(p + 3): 971235677\n\n*(p + 4): 618989504\n

\n","title":"Pointers and Functions in C++","authorDetails":{"name":"Vaaruni Agarwal","slug":"vaaruni-agarwal"},"description":"Learn how to use pointers and functions in C++ to improve the efficiency and flexibility of your programs. This tutorial covers the basics of pointers, including how to declare and manipulate pointers, as well as how to pass pointers to functions and use them to return values.","slug":"cpp/pointers-and-functions-in-cpp/","articleId":"636a83447bb1ce5072622bb0","bookmarkStatus":{"isBookmarked":false,"bookmarkId":null}}