Thinks To Note in C Language

Back in those days as I started as a teaching assistant (TA) we TAs would learn things which we never knew before. I am going add few things that I have learnt in TAing CS1111 this semester Apr-Jun 2021.

• " %c" the space before the %c matters! it prevents storing white space char.

  Otherwise it might consume the white space chars (such as ' ', '\t','\n') of the previous input eg scanf("%d%c", num, ch) taking input “11 a” implies num=11 and ch=' ' i.e a space in ch instead of intended a

• n=2i assignment is valid in C because the newer compilers have a complex constants as well.

  #include <stdio.h>
  int main(){
  int j=0;
  int k=3i;
  printf("i=%d k=%d",j,k);
  for(j=0; j<k; ++k)
    printf("j=%d\n",j);
  return 0;
  }
  

  So, this will not result in a compiler error as i undefined.

• clang and gcc may produce different output on using of uninitialized variables. One defaults to zero and other uses garbage value.
• We used Replit.com to running our labs. It can very much simulate a TA monitoring the students while coding. More about replt later.
• Never assign 0 to char in the char array and print it. It will either not print or have trouble with the output.
• Usage of bitwise-operator to make string of chars turn into: lower-case, upper-case and flip cases.