Output of C Programs | Set 15

Predict the output of below C programs.

Question 1

#include<stdio.h> int main(void) {   int a = 1;   int b = 0;   b = ++a + ++a;   printf("%d %d",a,b);   getchar();   return 0; }

Output: Undefined Behavior
See http://en.wikipedia.org/wiki/C_syntax#Undefined_behavior )



Question 2

#include<stdio.h>   int main() {   int a[] = {1, 2, 3, 4, 5, 6};   int *ptr = (int*)(&a+1);   printf("%d ", *(ptr-1) );   getchar();   return 0; }

Output: 6
&a is address of the whole array a[]. If we add 1 to &a, we get “base address of a[] + sizeof(a)”. And this value is typecasted to int *. So ptr – 1 points to last element of a[]

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