- C Programming Examples
- C Programming Examples
- C Print Hello World
- C Get Input from User
- C Print Integer
- C Add Two Numbers
- C Add Subtract Multiply Divide
- C Add n Numbers
- C Area Perimeter of Square
- C Area Perimeter of Rectangle
- C Area Circum of Circle
- C Fahrenheit to Celsius
- C Celsius to Fahrenheit
- C Inches to Centimeters
- C Kilogram to Gram
- C Reverse a Number
- C Swap Two Numbers
- C Interchange Numbers
- C Print ASCII Value
- C Print Fibonacci Series
- C Check Palindrome or Not
- C Check Armstrong or Not
- C Find Armstrong Numbers
- C Find nCr and nPr
- C Find Profit Loss
- C Sum of their Square
- C First & Last Digit Sum
- C Sum of All Digit
- C Product of All Digit
- C Print Total Digit in Number
- C Check Perfect Number
- C Find Basic Gross Salary
- C Round Number to Integer
- C Print Series upto n Term
- C Find Factors of Number
- C if-else & Loop 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
- C Is Reverse Equal Original
- C Make Calculator
- C Add Digits of Number
- Count Positive Negative Zero
- C Largest of Two Numbers
- C Largest of Three Numbers
- C Smallest of Two Numbers
- C Smallest of Three Numbers
- C Find Factorial of Number
- C Find LCM & HCF
- C Find LCM of n Numbers
- C Find HCF of n Numbers
- C Find Arithmetic Mean
- C Find Average, Percentage
- C Find Student Grade
- C Print Table of Number
- C Print Prime Numbers
- C Find Discount Purchase
- C Calculate Parcel Charge
- C Calculate Wage of Labor
- C Print Phone Bill
- C Conversion programs
- 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 Printing Programs
- C Print Diamond Pattern
- C Print Floyd's Triangle
- C Print Pascal's Triangle
- C Array Programs
- C 1D Array Programs
- C Linear Search
- C Binary Search
- C Largest Element in Array
- C Smallest Element in Array
- C Second Largest/Smallest
- C Count Even Odd
- C Array Element at Even
- C Array Element at Odd
- C Print Even Array Elements
- C Print Odd Array Elements
- C Sum/Product of Even/Odd
- 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 Print Common Elements
- C 2D Array Programs
- C Add Two Matrices
- C Subtract Two Matrices
- C Transpose a Matrix
- C Multiply Two Matrices
- C Sum All Matrix Elements
- C Largest Element in Matrix
- C Print Row Column Total
- C 3D Array Programs
- C String Programs
- C Print String
- C Find Length of String
- C Compare Two String
- C Copy a String
- C Concatenate String
- C Reverse a String
- C Count Vowels Consonants
- C Replace Vowel in String
- C Delete Vowels from String
- C Delete Word from String
- C Frequency of Character
- C Count Word in String
- C Remove Spaces from String
- C Sort a String
- C Sort String in Alphabetical
- C Sort Words in Ascending
- C Sort Words in Descending
- C Uppercase to Lowercase
- C Lowercase to Uppercase
- C Swap Two Strings
- C Check Anagram or Not
- C Check Palindrome String
- C Print Number in Words
- C Print Successive Character
- C Character without Space
- C File Programs
- C Read a File
- C Write Content to File
- C Read & Display File
- C Copy a File
- C Merge Two Files
- C Reverse File
- C Count All Character in File
- C List Files in Directory
- C Encrypt & Decrypt a File
- C Delete a File
- C Misc Programs
- Generate Random Numbers
- C Print Date Time
- C Print Message with Time
- C Get IP Address
- C Print Smiling face
- C Pass Array to Function
- Add Two Numbers using Pointer
- C Address of Variable
- C Shutdown Computer
- C Programming Tutorial
- C Tutorial
C Program to Concatenate Two Strings
In this article, we will learn about how to concatenate two strings with and without using library functions. Let's first start with concatenating strings using a library function.
Concatenate a string in C using the library function
To concatenate or append one string to another string in C programming, you have to ask the user to enter any two strings and concatenate both the strings using the strcat() function, as shown here in the program given below. The function accepts two arguments: strcat(str1, str2). Here, the string value of str2 will be appended at the end of string str1.
#include<stdio.h> #include<conio.h> #include<string.h> int main() { char str1[50], str2[50]; printf("Enter first string: "); gets(str1); printf("Enter second string: "); gets(str2); strcat(str1, str2); printf("\nString after concatenation is:\n%s", str1); getch(); return 0; }
The program was written in the Code::Blocks IDE; therefore, after a successful build and run, you will get the following output:
Now supply the value of the first string, say codes, and press the ENTER key. Then supply the string value for the second string, say cracker, and finally press the ENTER key to see the concatenated string as shown in the snapshot given here:
The value of the second string cracker (in this case) gets copied into the first string codes, and the concatenated string will become codescracker as shown in the output. If we use the function strcat() as strcat(str2, str1), then the string value of str1 will get copied to str2. Therefore, if we supply codes for str1 and cracker for str2. Then strcat(str2, str1) will output the concatenated string as crackercodes.
Concatenate a string in C without using the strcat() function
Now let's create another program that will also concatenate strings, but this time without using any library functions.
#include<stdio.h> #include<conio.h> int main() { char strOne[50], strTwo[50], i, count=0; printf("Enter first string: "); gets(strOne); printf("Enter second string: "); gets(strTwo); for(i=0; strOne[i]!='\0'; i++) count++; for(i=0; strTwo[i]!='\0'; i++) { strOne[count] = strTwo[i]; count++; } strOne[count] = '\0'; printf("\nString after concatenation is:\n%s", strOne); getch(); return 0; }
The program is created in such a way that the value of the second string (strTwo) will get concatenated into the first string (strOne). And the program will print the value of the concatenated string as output, as shown in the sample run given below:
Program Explained
- Using the gets() function, obtain two string values from the user.
- The first string, say codes, is initialized to strOne, and second string, say cracker, is initialized to strTwo.
- Create a for() loop to get the length of the first string, strOne.
- If the string reaches the null-terminated character ('\0'), it means that there is nothing left inside it.
- After exiting from the for() loop, we will have a count variable that contains the length of the string strOne.
- We have calculated the length of the first string to append the content of the second string into the first from the place where the first string ends.
- Create another for() loop to append the content of the second string, strTwo into the first string, strOne.
- After appending all of strTwo's characters, append a null-terminated character ('\0') to the end of strOne.
- Print the final value of strOne, which will be the concatenated string.
Concatenate two strings into a third
Another program that will read any two strings from the user and concatenate them into a third string without using any library functions is as follows:
#include<stdio.h> #include<conio.h> int main() { char strOne[50], strTwo[50], strCon[100], i, count=0; printf("Enter first string: "); gets(strOne); printf("Enter second string: "); gets(strTwo); for(i=0; strOne[i]!='\0'; i++) { strCon[i] = strOne[i]; count++; } for(i=0; strTwo[i]!='\0'; i++) { strCon[count] = strTwo[i]; count++; } strCon[count] = '\0'; printf("\nString 1 = %s", strOne); printf("\nString 2 = %s", strTwo); printf("\nConcatenated String = %s", strCon); getch(); return 0; }
After a successful build and run, here is the first snapshot of the sample run:
Provide any two strings, say codes and cracker, then press the ENTER key to see the three strings. The first and second strings are the strings the user has provided, and the third string will be the concatenated string. Here is the second snapshot of the sample run:
The same program in different languages
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