WAP to concatenate /merge two strings without using strcat() function.

in turboc++
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//WAP to concatenate  two strings  without using(strcat()) function.
#include <stdio.h>
#include<string.h>
#include<conio.h>
int main()
{
    char st[100],st1[100];//two string declaration
    int i,j;
    printf("enter first string\n");
    //fgets(name, sizeof (name), stdin);//to input string with space
    scanf("%s",st); //it also CAN BE USED. IT accepts string with space until it meets new line
    printf("enter second string\n");
    scanf("%s",st1);
     for(i=0;st[i]!='\0';i++);//to get last value of i of first string
    for(j=0;st1[j]!='\0';j++)//loop execution till null character
    {

        st[i]=st1[j];//copying characters
        i++;
    }

    st[i]='\0';//adds an extra null character at the end.

       printf("concatenated string =%s\n",st);//prints the merged string
   getch();
    return 0;
}
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in codeblocks:
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//WAP to concatenate  two strings  without using(strcat()) function.
#include <stdio.h>
#include<string.h>
int main()
{
    char st[100],st1[100];//two string declaration
    int i,j;
    printf("enter first string\n");
    //fgets(name, sizeof (name), stdin);//to input string with space
    scanf("%s",st); //it also CAN BE USED. IT accepts string with space until it meets new line
    printf("enter second string\n");
    scanf("%s",st1);
     for(i=0;st[i]!='\0';i++);//to get last value of i of first string
    for(j=0;st1[j]!='\0';j++)//loop execution till null character
    {

        st[i]=st1[j];//copying characters
        i++;
    }

    st[i]='\0';//adds an extra null character at the end.

       printf("concatenated string =%s\n",st);//prints the merged string
    return 0;
}