Lecture 128:- Let's Put all together in C++ program for array

In C and C++, the length of a string can be determined using two common approaches:

1. Using Standard Library Function: In C++, you can use the std::string class member function length() or size() to find the length of a string. In C, you can use the strlen() function from the <cstring> header to find the length of a null-terminated character array (string).
2. Manually Calculating Length: In C, if you are working with a character array, you can calculate the length of the string manually by iterating through the array until you encounter the null character ('\0').

Here are examples of both approaches:

Using Standard Library Function (C++):

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#include <iostream> #include <string> int main() {    std::string str = "Hello, World!";    int length = str.length(); // or str.size();    std::cout << "Length of the string: " << length << std::endl;    return 0; }

Using Standard Library Function (C):

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#include <stdio.h> #include <string.h> int main() {    const char str[] = "Hello, World!";    int length = strlen(str);    printf("Length of the string: %d\n", length);    return 0; }

Manually Calculating Length (C):

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#include <stdio.h> int main() {    const char str[] = "Hello, World!";    int length = 0;    while (str[length] != '\0') {        length++;    }    printf("Length of the string: %d\n", length);    return 0; }

In all three examples, the program calculates and outputs the length of the string "Hello, World!" using different methods. The output will be:

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Length of the string: 13

Using the standard library function is more convenient and efficient, especially in C++, where the std::string class abstracts the string handling. In C, if you are working with character arrays, manually calculating the length may be necessary if you don't want to rely on the <cstring> library. However, be careful to ensure that the character array is null-terminated to avoid undefined behavior while calculating its length manually.