Program to concatenate two strings

#include<stdio.h>
#include<conio.h>

void main()
{
char s1[20],s2[20],s3[40];
int i,j;
clrscr();

printf("\n Enter first string : ");
gets(s1);
printf("\n Enter second string : ");
gets(s2);

for(i=0;s1[i]!='\0';++i)
s3[i]=s1[i];

for(j=0;s2[j]!='\0';++j)
s3[i+j]=s2[j];

s3[i+j]='\0';

printf("\n The concatenated string is : %s",s3);
getch();
}


                                                           Output