- 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 Copy One String to Another
In this article, you will learn and get code on copy one string to another in C++. The program is created with following approaches:
- Copy String without using strcpy() Function
- Using Pointer
- Using user-defined Function
- Using library function, strcpy()
Copy String without using strcpy() Function
This program copies the string (entered by user at run-time) without using any library function like strcpy() Let's have a look at the program first. Its explanation is given later on:
The question is, write a program in C++ that copies one string to another. Here is its answer:
#include<iostream> #include<stdio.h> using namespace std; int main() { char strOrig[100], strCopy[100], i=0; cout<<"Enter the string: "; gets(strOrig); while(strOrig[i]!='\0') { strCopy[i] = strOrig[i]; i++; } strCopy[i] = '\0'; cout<<"\nEntered String: "<<strOrig; cout<<"\nCopied String: "<<strCopy; cout<<endl; return 0; }
This program was build and run under Code::Blocks IDE. Here is its sample run:
Now enter the string say codescracker and press ENTER
key to copy it to another string.
Here is the final snapshot of its sample run:
The dry run of above program with user input, codescracker goes like:
- Initial value, i=0
- When user enters the string say codescracker, it gets stored in a variable, strOrig[] in
following way:
- strOrig[0]=c
- strOrig[1]=o
- strOrig[2]=d
- strOrig[3]=e
- strOrig[4]=s
- strOrig[5]=c
- strOrig[6]=r
- strOrig[7]=a
- strOrig[8]=c
- strOrig[9]=k
- strOrig[10]=e
- strOrig[11]=r
- That is, the first character (c) of the string (codescracker) gets stored at very first index (0) of the strOrig[]. And the second character (o) gets stored at second index (1), and so on.
- Because the maximum size of strOrig[] is 100, and the entered string is only of 12 character long, therefore at 12th index (index after the last character's index), a null terminated character (\0) gets automatically initialized. That indicates the end of string, or no any character left in strOrig from this (12th) index.
- Now the condition, strOrig[i]!='\0' or strOrig[0]!='\0' or c!='\0' evaluates to be true, therefore program flow goes inside the loop and the 0th index's character of strOrig[] gets initialized to strCopy[] at same index
- That is, strOrig[i] or strOrig[0] or c gets initialized to strCopy[i] or strCopy[0]
- Now the value of i gets incremented. So i=1
- Program flow goes back and evaluates the condition of while loop again.
- Because a null terminated character (\0) is available at 12th index, therefore both the statements (availabe in the body of while loop) gets executed 12 times
- Therefore all the characters gets copied to strCopy[] variable one by one
- And when the execution of while loop gets ended, don't forgot to initialize a null terminated character at the index after last character's index
- Now just print the value of both the variables say strOrig[] and strCopy[]
Copy String using Pointer
This program copies the string using pointer. The question is, write a program in C++ to copy the content of one string to another using pointer. Here is its answer:
#include<iostream> #include<stdio.h> using namespace std; int main() { char strOrig[100], strCopy[100]; char *origPtr, *copPtr; cout<<"Enter the string: "; gets(strOrig); origPtr = &strOrig[0]; copPtr = &strCopy[0]; while(*origPtr) { *copPtr = *origPtr; origPtr++; copPtr++; } *copPtr = '\0'; cout<<"\nEntered String: "<<strOrig; cout<<"\nCopied String: "<<strCopy; cout<<endl; return 0; }
Here is its sample run with user input, Hello codescracker
The statement,
origPtr = &strOrig[0];
initializes the initial address of strOrig[] variable. That is its 0th index's address. And the statement,
copPtr = &strCopy[0];
also initializes the 0th index's address of strCopy[]
Note - If a pointer type variable holds address of any variable that contains some values, then anything happened with the variable (pointer) makes changes to original. Because it holds its address, not value. So any operation perform through pointer type variable, directly effects the value at that address.
The * is called as value at operator. And & is called as address of operator.
The statement, origPtr++;
means, origPtr now holds next index's address.
So using pointer also, all the character of original string gets copied (in one-by-one manner) to strCopy[]
Copy String using User-defined Function
This program also copies one string to another, but using a user-defined function named cpystr()
#include<iostream> #include<stdio.h> using namespace std; void cpystr(char *, char *); int main() { char strOrig[100], strCopy[100]; cout<<"Enter the string: "; gets(strOrig); cpystr(strOrig, strCopy); cout<<"\nEntered String: "<<strOrig; cout<<"\nCopied String: "<<strCopy; cout<<endl; return 0; } void cpystr(char *origPtr, char *copPtr) { while(*origPtr) { *copPtr = *origPtr; origPtr++; copPtr++; } *copPtr = '\0'; }
This program produces the same output as of previous program.
Using strcpy() Function
This is the last program that uses a library function of C++, named strcpy() to copy string. It takes two string as its argument. The value of second argument gets copied to first.
#include<iostream> #include<stdio.h> #include<string.h> using namespace std; int main() { char strOrig[100], strCopy[100]; cout<<"Enter the string: "; gets(strOrig); strcpy(strCopy, strOrig); cout<<"\nEntered String: "<<strOrig; cout<<"\nCopied String: "<<strCopy; cout<<endl; return 0; }
Same Program in Other Languages
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