Why does the arrow (->) operator in C exist?

Summary

I'll interpret your question as two questions: 1) why -> even exists, and 2) why . does not automatically dereference the pointer. Answers to both questions have historical roots. Why does -> even exist? In one of the very first versions of C language (which I will refer as CRM for "C Reference Manual", which came with 6th Edition Unix in May 1975), operator -> had very exclusive meaning, not synonymous with * and . combination The C language described by CRM was very different from the modern C in many respects. In CRM struct members implemented the global concept of byte offset, which could be added to any address value with no type restrictions. I.e. all names of all struct members had independent global meaning (and, therefore, had to be unique). For example you could declare struct S { int a; int b; }; and name a would stand for offset 0, while name b would stand for offset 2 (assuming int type of size 2 and no padding). The language required all members of all structs in the translation unit either have unique names or stand for the same offset value. E.g. in the same translation unit you could additionally declare struct X { int a; int x; }; and that would be OK, since the name a would consistently stand for offset 0. But this additional declaration struct Y { int b; int a; }; would be formally invalid, since it attempted to "redefine" a as offset 2 and b as offset 0. And this is where the -> operator comes in. Since every struct member name had its own self-sufficient global meaning, the language supported expressions like these int i = 5; i->b = 42; /* Write 42 into `int` at address 7 */ 100->a = 0; /* Write 0 into `int` at address 100 */ The first assignment was interpreted by the compiler as "take address 5, add offset 2 to it and assign 42 to the int value at the resultant address". I.e. the above would assign 42 to int value at address 7. Note that this use of -> did not care about the type of the expression on the left-hand side. The left hand side was...