concatenate one string with another string given by the user .

#include<stdio.h>
#include<conio.h>
main()
{
  char source[20],source1[20];
  int i=0,j=0;

  printf("enter the 1st string :\n");
  scanf("%s",source);

  printf("enter the 2nd string :\n");
  scanf("%s",source1);

  while(source[i] != '\0')
  
    i++;
    
    while(source1[j] != '\0')
    {
     source[i]=source1[j];
     i++;
     j++;
    }
    
  
    source[i]='\0';
  
  printf(" string after concatenation %s", source);
  
  

}

enter the 1st string :
rahul
enter the 2nd string :
chaurasiya
 string after concatenation rahulchaurasiya