C Program to Concatenate Two Strings without using strcat() Function

C – Strings : 

Strings are actually one-dimensional array of characters terminated by a null character ‘\0’. Thus a null-terminated string contains the characters that comprise the string followed by a null.

String is a sequence of characters. char data type is used to represent one single character in C. So if you want to use a string in your program then you can use an array of characters.

The declaration and definition of the string using an array of chars is similar to declaration and definition of an array of any other data type.

Any string ends with a terminating null character ‘\0’. An array definition in such a way should include null character ‘\0’ as the last element.

Here is source code of the C Program to Concatenate Two Strings without using strcat() Function. The C program is successfully compiled and run(on Codeblocks) on a Windows system. The program output is also shown in below.

SOURCE CODE : :

/*  C Program to Concatenate Two Strings without using strcat() Function  */

#include<stdio.h>
int main()
{
    int i=0,j=0;
    char str1[20],str2[20];

    printf("\nEnter first string :: ");
    gets(str1);
    printf("\nEnter second string :: ");
    gets(str2);

    printf("\nBefore Concatenation, Strings are :: \n\n");
    puts(str1);
    puts(str2);

    while(str1[i]!='\0')
    {
        i++;
    }

    while(str2[j]!='\0')
    {
        str1[i++]=str2[j++];
    }

    str1[i]='\0';

    printf("\nAfter Concatenation, Strings are :: \n\n");
    puts(str1);

    return 0;
}

OUTPUT : :

/*  C Program to Concatenate Two Strings without using strcat() Function  */

Enter first string :: Codez

Enter second string :: Club

Before Concatenation, Strings are ::

Codez
Club

After Concatenation, Strings are ::

CodezClub

Process returned 0

Above is the source code for C Program to Concatenate Two Strings without using strcat() Function which is successfully compiled and run on Windows System.The Output of the program is shown above .