- 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 Concatenate Two Strings
Here you will learn and get code on string concatenation in C++. The program to concatenate string is created in following ways:
- String Concatenation without using Library Function strcat()
- Using strcat()
- Using + operator
- Using Pointer
String Concatenation without strcat()
This program concatenates or appends second string into first without using any library function like strcat():
#include<iostream> #include<stdio.h> using namespace std; int main() { char strOne[100], strTwo[50], i, j=0; cout<<"Enter the First String: "; gets(strOne); cout<<"Enter the Second String: "; gets(strTwo); for(i=0; strOne[i]!='\0'; i++) j++; for(i=0; strTwo[i]!='\0'; i++) { strOne[j] = strTwo[i]; j++; } strOne[j] = '\0'; cout<<"\nString after Concatenation: "<<strOne; cout<<endl; return 0; }
This program was build and run under Code::Blocks IDE. Here is its sample run:
Now supply any string as input say codes and then another string as input say cracker. Press
ENTER
key to add the second string cracker to first one codes as shown in the output given
below:
Here is another sample run with user input, this is as first string and codescracker as second string:
Note - Don't forgot to enter space after this is or before codescracker while entering the first or second string. Otherwise, both the string gets concatenated without space like this iscodescracker.
The following two statements:
strOne[j] = strTwo[i]; j++;
can also be replaced with:
strOne[j++] = strTwo[i];
That is, a post increment to j is used, that increments its value by 1 after evaluating the statement:
strOne[j] = strTwo[i];
If user enters first string as codes, then it gets initialized to strOne in a way that:
- First character (c) gets initialized to strOne[0]
- Similarly, strOne[1]=o, strOne[2]=d, strOne[3]=e, strOne[4]=s
And if user enters cracker as second string, then it also gets initialized to strTwo in similar way. Therefore with this two string input, the dry run of above program goes like:
- At first execution of for loop, 0 gets initialized to i and checks the condition, strOne[i]!='\0' or strOne[0]!='\0' or c!='\0'.
- The condition evaluates to be true. Because, c is not equal to a null terminated character
- Therefore program flow goes inside the loop and increments the value of j
- Then program flow goes back to update part of for loop, increments the value of i and checks for the condition again with new value of i
- This process continues until the condition evaluates to be true
- Because the first string is codes, therefore at fifth time, condition evaluates to be false, and program flow exits the loop, and goes to second for loop. Now the value of j is 5
- Therefore, from 5th index, all the characters (one by one) of second string gets initialized to
the first string in a way that:
- First character of second string (c) gets initialized to strOne[5]
- Second character of second string (r) gets initialized to strOne[6]
- Similarly, strOne[7]=a, strOne[8]=c, strOne[9]=k, strOne[10]=e, strOne[11]=r
- And after exiting the loop, \0 gets initialized to strOne[12]
- Print the value of strOne that equals codescracker
String Concatenation using strcat()
The function strcat() takes two strings as argument. The value of second string gets appended or concatenated to first string. For example, if there are two string say strOne and strTwo. And the value of both strings are:
strOne = "codes"; strTwo = "cracker";
Then,
strcat(strOne, strTwo);
Means now strOne = codescracker. That is, the value of second string concatenated to first one. This function is defined in string.h library
#include<iostream> #include<stdio.h> #include<string.h> using namespace std; int main() { char strOne[100], strTwo[50]; cout<<"Enter the First String: "; gets(strOne); cout<<"Enter the Second String: "; gets(strTwo); strcat(strOne, strTwo); cout<<"\nString after Concatenation: "<<strOne; cout<<endl; return 0; }
This program will produce the same output as of previous one.
String Concatenation using + Operator
The question is, write a program in C++ to concatenates two strings using + operator. The answer to this question is given below:
#include<iostream> using namespace std; int main() { string strOne="", strTwo="", strThree=""; cout<<"Enter the First String: "; cin>>strOne; cout<<"Enter the Second String: "; cin>>strTwo; strThree = strOne + strTwo; cout<<"\nString after Concatenation: "<<strThree; cout<<endl; return 0; }
Here is its sample run with user input, codes and cracker as first and second string:
Note - Previous program will only work with string input without any space.
String Concatenation using Pointer
This is the last program, that concatenates two strings using pointer.
#include<iostream> #include<stdio.h> using namespace std; int main() { char strOne[100], strTwo[50]; char *firstString, *secondString; cout<<"Enter the First String: "; gets(strOne); cout<<"Enter the Second String: "; gets(strTwo); firstString = strOne; secondString = strTwo; while(*firstString) firstString++; while(*secondString) { *firstString = *secondString; firstString++; secondString++; } *firstString = '\0'; cout<<"\nString after Concatenation: "<<strOne; cout<<endl; return 0; }
Here is its sample run with user input, C++ Program to as first string and Concatenate Two Strings as second string:
The address of both the string strOne and strTwo gets initialized to its corresponding pointers, say firstString and secondString. And based on the address, we've concatenates the second string's value to the first one. To learn more about pointer in C++, you can follow its separate tutorial
Note - The * is called as value at operator
Same Program in Other Languages
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