#9. Concepts in C -- only through Examples & Explanations

This is a continuation of last post. 

Before seeing the answer try to predict it & then see the explanation.

All the Best!!

11. main()
{
char string[]="Hello World";
display(string);
}
void display(char *string)
{
printf("%s",string);
}


12. main()
{
int c=- -2;
printf("c=%d",c);
}

13. #define int char
main()
{
int i=65;
printf("sizeof(i)=%d",sizeof(i));
}

14. main()
{
int i=10;
i=!i>14;
Printf ("i=%d",i);
}

15. #include<stdio.h>
main()
{
char s[]={'a','b','c','\n','c','\0'};
char *p,*str,*str1;
p=&s[3];
str=p;
str1=s;
printf("%d",++*p + ++*str1-32);
}

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11.
Answer:
Compiler Error : Type mismatch in redeclaration of function display
Explanation :
In third line, when the function display is encountered, the compiler doesn't
know anything about the function display. It assumes the arguments and return types to be integers, (which is the default type). When it sees the actual function display, the arguments
and type contradicts with what it has assumed previously. Hence a compile time error occurs.

12.
Answer:
c=2;
Explanation:
Here unary minus (or negation) operator is used twice. Same maths rules
applies, ie. minus * minus= plus.
Note:
However you cannot give like --2. Because -- operator can only be applied to
variables as a decrement operator (eg., i--). 2 is a constant and not a variable.

13.
Answer:
sizeof(i)=1
Explanation:
Since the #define replaces the string int by the macro char

14.
Answer:
i=0

Explanation:
In the expression !i>14 , NOT (!) operator has more precedence than ‘ >’
symbol. ! is a unary logical operator. !i (!10) is 0 (not of true is false). 0>14 is false (zero).

15.
Answer:
77
Explanation:
p is pointing to character '\n'. str1 is pointing to character 'a' ++*p. "p is pointing to '\n'
and that is incremented by one." the ASCII value of '\n' is 10, which is then incremented to 11.
The value of ++*p is 11. ++*str1, str1 is pointing to 'a' that is incremented by 1 and it becomes
'b'. ASCII value of 'b' is 98.
Now performing (11 + 98 – 32), we get 77("M");
So we get the output 77 :: "M" (Ascii is 77).
========================================================

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