sir, in this given problem, if adjacent elements are equal then we are adding s[0]+string()+res why can’t we add s[0]+""+res I tried using the latter on but its giving an error for me also in not work the " " directs adds up to string but why its not happening here.
Thanks 
Anyone who can answer?
See this first answer https://stackoverflow.com/questions/4304662/concatenating-strings-doesnt-work-as-expected
Bhaiya then do char pointer ko add Karne mai kya dikkat hai ?
It’s because addition with pointers works different. They are addresses.
See this https://stackoverflow.com/questions/18468229/concatenate-two-char-strings-in-a-c-program/18468387 and https://stackoverflow.com/questions/394767/pointer-arithmetic
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