Common String Functions (from <cstring> library)

Function Description strlen(str) Returns length of the string strcpy(dest, src) Copies one string into another strcat(str1, str2) Concatenates two strings strcmp(str1, str2) Compares two strings lexicographically

In C++, the library provides several standard functions to manipulate strings effectively. Each string function serves a specific purpose:

1. strlen(str): This function returns the length of a string without counting the null character at the end of the string.
2. strcpy(dest, src): This function copies the contents of the source string (src) into the destination string (dest).
3. strcat(str1, str2): This function concatenates (appends) the second string (str2) to the end of the first string (str1).
4. strcmp(str1, str2): This function compares two strings lexicographically, meaning it checks their alphabetical order.

Think of the string functions as tools in a toolbox. Just as you might have one tool to measure a length (like a ruler), another tool to copy a design (like a photocopier), a mechanism to attach one object to another (like glue), and a scale to compare weights (like a weighing scale), these string functions help you manage and manipulate strings in programming effectively.

Example cpp char str1[20] = "Hello"; char str2[20] = "World"; strcat(str1, str2); // str1 becomes "HelloWorld"

In this example, we declare two character arrays (strings):

• str1 is initialized with "Hello" and
• str2 is initialized with "World". By using the strcat() function, we concatenate str2 to str1. After this operation, str1 will hold the value "HelloWorld". This demonstrates how string functions can modify existing strings by combining them.

Imagine you have a first name 'Hello' written on a piece of paper and a last name 'World' on another piece of paper. If you want to merge them to form a full name 'HelloWorld', you take the two pieces of paper and write them down on one sheet together. That's like what strcat() does for strings in your code.