In this article, you will learn and get to find and print the length of any given string by user at run-time, in C++ language. The program is created with the help of these approaches:
To find length of a string in C++ programming, you have to ask from user to enter the string first. And then find its length as shown in the program given below.
This program finds length of a string using user-based code. That is, this program does not use library function or built-in function, strlen().
// C++ Find Length of String without strlen() Function
// ----codescracker.com----
#include<iostream>
#include<stdio.h>
using namespace std;
int main()
{
char str[200];
int len=0, i=0;
cout<<"Enter the String: ";
gets(str);
while(str[i])
{
len++;
i++;
}
cout<<"\nLength = "<<len;
cout<<endl;
return 0;
}
This program was build and run under Code::Blocks IDE. Here is its sample run:
Now enter any string say codes cracker dot com and press ENTER key to find and print length
of given string as shown here in the following output:
Here is another sample run with user input, codescracker:
The dry run of above program with user input, codescracker goes like:
Here is another C++ program that also finds and prints length of string entered by user. The only difference with previous program is, this program uses a built-in or library function of C++ named strlen().
The function, strlen() takes string as its argument and returns its length. This function is defined in string.h header file.
// C++ Find Length of String using strlen() Function
// ----codescracker.com----
#include<iostream>
#include<stdio.h>
#include<string.h>
using namespace std;
int main()
{
char str[200];
int len=0;
cout<<"Enter the String: ";
gets(str);
len = strlen(str);
cout<<"\nLength = "<<len;
cout<<endl;
return 0;
}
The output produced by this program is similar to previous program.
Now let's create the same purpose program, that is to find length of a string, but using pointer. The address of first character of string gets initialized to pointer type variable say ptr and using this variable, the length of string gets calculated.
Note - The & is called as address of operator. Whereas as the * is called as value at operator. The ptr++ (char pointer type variable) moves to next character's address
// C++ Find Length of String using Pointer
// ----codescracker.com----
#include<iostream>
#include<stdio.h>
using namespace std;
int main()
{
char str[200], *ptr;
int len=0;
cout<<"Enter the String: ";
gets(str);
ptr = &str[0];
while(*ptr)
{
len++;
ptr++;
}
cout<<"\nLength = "<<len;
cout<<endl;
return 0;
}