Thread: array and pointer problem

//c program

Code:

#include <stdio.h>


int main(void) {
    static int arr[] = {97, 98, 99, 100, 101, 102, 103, 104 };
                       
     int * ptr = arr + 1;
                                                 
      print(++ptr, ptr--, ptr, ptr++, ++ptr);
                                                                                  
      return 0;
}


int print(int *a, int *b, int *c, int *d, int *e)
{
   printf("%d %d %d %d %d \n", *a, *b, *c, *d, *e);
                 
}

Expected Output of program by me:
99 99 98 98 100

Actual Output of program:
100 100 100 99 100


Could you please explain the Actual output?

Two problems:
1. In C there's no guarantee about the order in which a function's arguments are evaluated.
2. You're not allowed to modify the same variable more than once per "sequence point". Question 3.8

Compiling your program with gcc and full warnings gives multiple "sequence point" warnings. (You also forgot to prototype your print function and are not returning the promised int.)

Although an explanation for the exact values you received could be garnered from the assembly code, it would be essentially meaningless since this is undefined behaviour.