- C++ Programming Examples
- C++ Programming Examples
- C++ Hello World
- C++ Get Input
- C++ Print Integer
- C++ Add Two Numbers
- C++ Add Sub Mul Div
- C++ Add Digits
- C++ Find Average Perc
- C++ Find Arithmetic Mean
- C++ Sum of n Natural Numbers
- C++ Sum of n Numbers
- C++ Area Perimeter of Square
- C++ Area Perimeter of Rectangle
- C++ Area Perimeter of Triangle
- C++ Area Circum of Circle
- C++ Find Simple Interest
- C++ Fahrenheit to Celsius
- C++ Celsius to Fahrenheit
- C++ Print Prime Numbers
- C++ Reverse a Number
- C++ Swap Two Numbers
- C++ Print Multiplication Table
- C++ Find Factorial of Number
- C++ Find Factors of Number
- C++ Find HCF & LCM
- C++ Make Calculator
- C++ Count Digits in Number
- C++ Sum of First & Last Digit
- C++ Product of Digits of Number
- C++ Sum of Squares of Digits
- C++ Interchange Digits of Number
- C++ if else Programs
- C++ Check Even or Odd
- C++ Check Prime or Not
- C++ Check Alphabet or Not
- C++ Check Vowel or Not
- C++ Check Leap Year or Not
- Check Reverse equal Original
- C++ Check Perfect Number
- C++ Check Palindrome or Not
- C++ Check Armstrong or Not
- C++ Divisibility Test
- C++ Find Wage of Labor
- C++ Find Discounted Price
- C++ Find Shipping Charge
- C++ Find Telephone Bills
- C++ Calculate Student Grade
- C++ Largest of Two Numbers
- C++ Largest of Three Numbers
- C++ Number Conversion
- C++ Decimal to Binary
- C++ Decimal to Octal
- C++ Decimal to Hexadecimal
- C++ Binary to Decimal
- C++ Binary to Octal
- C++ Binary to Hexadecimal
- C++ Octal to Decimal
- C++ Octal to Binary
- C++ Octal to Hexadecimal
- C++ Hexadecimal to Decimal
- C++ Hexadecimal to Binary
- C++ Hexadecimal to Octal
- C++ Pattern Programs
- C++ Pattern Programs
- C++ Print Diamond Pattern
- C++ Print Floyd's Triangle
- C++ Print Pascal's Triangle
- C++ Array Programs
- C++ 1D Array Program
- C++ Linear Search
- C++ Binary Search
- Find Largest Element in Array
- Find Smallest Element in Array
- Find Second Largest Element
- Find Second Smallest Element
- C++ Sum of All Elements
- C++ Multiply All Elements
- C++ Element on Even Position
- C++ Element on Odd Position
- C++ Print Even Numbers in Array
- C++ Print Odd Numbers in Array
- C++ Count Even/Odd Numbers
- C++ Sum of Even/Odd Numbers
- C++ Count Positive Negative Zero
- C++ Reverse an Array
- C++ Insert Element in Array
- C++ Delete Element from Array
- C++ Merge two Arrays
- C++ Bubble Sort
- C++ Selection Sort
- C++ Insertion Sort
- C++ Common Elements
- C++ 2D Array Programs
- C++ Add Two Matrices
- C++ Subtract Two Matrices
- C++ Transpose Matrix
- C++ Multiply Two Matrices
- C++ 3D Array Programs
- C++ String Programs
- C++ Print String
- C++ Find Length of String
- C++ Compare Two Strings
- C++ Copy String
- C++ Concatenate String
- C++ Reverse a String
- C++ Delete Vowels from String
- C++ Delete Word from String
- C++ Count Character in String
- C++ Count Word in String
- C++ Frequency of Word
- C++ Remove Spaces from String
- C++ Sort a String
- C++ Uppercase to Lowercase
- C++ Lowercase to Uppercase
- C++ Swap Two Strings
- C++ Check Anagram or Not
- C++ Capitalize All Words in String
- C++ Capitalize Specific Character
- C++ Get Numbers from String
- C++ File Programs
- C++ Read a File
- C++ Write Content to File
- C++ Append Data in File
- C++ Read & Display File
- C++ Copy a File
- C++ Merge Two Files
- Count Characters, Words in File
- C++ Capitalize All Words in File
- C++ List Files in Directory
- C++ Delete a File
- C++ Encrypt & Decrypt a File
- C++ Misc Programs
- C++ Print ASCII Value
- C++ Add Binary Numbers
- C++ Generate Random Numbers
- C++ Print Smiling Face
- C++ Days into Years, Months
- Add Two Numbers using Pointer
- C++ Print Fibonacci Series
- Generate Armstrong Numbers
- C++ Find nCr and nPr
- C++ Get IP Address
- C++ Print Date/Time
- C++ Shutdown, Restart Computer
- C++ Programming Tutorial
- C++ Tutorial
- C++ Programming Test
- C++ Programming Test
- Give Online Test
- All Test List
C++ Program to Find Length of String
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:
- Find length of string without using any library or built-in function like strlen()
- using strlen() function
- using Pointer
Find Length of String without strlen() Function
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().
#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:
- Initial values, len=0, i=0
- When user enters the string say codescracker as input, then it gets stored to str[] in this way:
- str[0]=c
- str[1]=o
- str[2]=d
- and so on upto
- str[11]=r
- Now the condition of while loop gets evaluated. That is the condition, str[i] or str[0] or c evaluates to be true. Therefore program flow goes inside the loop
- When there is no any character left, then the condition evaluates to be false. That is, its condition evaluates to be false at 12th index
- Now inside the loop, the value of len and i gets incremented. So i=1 and len=1
- Program flow goes back and evaluates the condition again. Because the condition str[i] or str[1] again evaluates to be true, therefore program flow again goes inside the loop.
- This process continues until the last character of codescracker.
- And every time the value of len gets incremented
- So when the condition of while loop evaluates to be false, then we'll have a variable, len that holds the length of string, or how many characters are available in the entered string by user at run-time
- So print the value of len as output that shows the length of given string
Find Length of String using strlen() Function
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.
#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.
Find Length of String using Pointer
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
#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; }
Same Program in Other Languages
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