C program to concatenate two strings without using library function

Write a program to concatenate two strings. (Do not use inbuilt string function).

#include<stdio.h>
int main()
{
	char str1[50],str2[30];
	int a,b;
	printf("Enter String 1");
	gets(str1);	
	printf("Enter String 2");
	gets(str2);
	for(a=0;str1[a]!='\0';a++);
	for(b=0;str2[b]!='\0';b++)
	{
		str1[a]=str2[b];
		a++;
	}
	str1[a]='\0';
	printf("Result String : %s",str1);
	return 0;
}

Enter String 1infomax

Enter String 2academy

Result String : infomaxacademy