Drivers Firmware

#include<stdio.h>
int main()
{
char a[100],b[100];
 int length=0;
int i,j;
 printf("Enter the first string ");
 gets(a);

 printf("Enter the second string ");
 gets(b);
 for(i=0;a[i]!=;i++)
 {
 length=length+1;
 }
 for(i=length,j=0;a[j]!=;i++,j++)
 {
 a[i]=b[j];
 }
 printf("The new string is:");
 puts(a);
 return 0;
}