Program:
 #include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
char str[20],str1[20],str2[20];
int i,j;
clrscr();
i=j=0;
printf("\n Enter 1st string:");
scanf("%s",&str);
printf("\n Enter 2nd string:");
scanf("%s",&str1);
while(str[i]!='\0')
{
str2[i]=str[i];
i++;
}
while(str1[j]!='\0')
{
str2[i]=str1[j];
i++;
j++;
}
str2[i]='\0';
printf("\n Resultant string is:%s",str2);
getch();
}