C Program to Concatenate Two Strings Using Pointers

Character array is called string. The last character is always null in a string represented by \0. The indexing always start from 0 in any array.
In the following program pointers are used to copy the value of bb string to aa string

//C program to concatenate strings using pointers

#include <stdio.h>
int main()
{
    char aa[100], bb[100];	//array declaration
    printf("\nThe string after concatenation is: %s ", aa); 
    printf("\nEnter the first string: ");
    gets(aa);    	//using gets allows us to take string inputs along with spaces
    printf("\nEnter the second string to be concatenated: ");
    gets(bb);   

    char *a = aa;
    char *b = bb;
    
    while(*a)   
    {
        a++;    
    }
    while(*b)   
    {
        *a = *b;
        b++;
        a++;
    }
    *a = '\0';  			// string must end with '\0'
    printf("\n\n\nThe string after concatenation is: %s ", aa);
    return 0;
}

Output