Execution of printf with ++ operators

Consider below C++ program and predict its output.

printf("%d %d %d", i, ++i, i++);

The above invokes undefined behaviour by referencing both ‘i’ and ‘i++’ in the argument list. It is not defined which order the arguments are evaluated. Different compilers may choose different orders. A single compiler can also choose different orders at different times.

For example below three printf statements also cause undefined behavior.

// All three pritf() statements in this cause undefined behavior

int main()
    int a = 10;
    printf("\n %d %d", a, a++); 
    a = 10;
    printf("\n %d %d", a++, a);
    a = 10;
    printf("\n %d %d %d ", a, a++, ++a);
    return 0;

Therefore, it is not recommended to do two or more than two pre or post increment operators in the same statement.

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