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cprintfpointer-arithmeticpost-increment

Having trouble regarding output of a printf statement

I am having some trouble understanding the output of the following code snippet.

#include<stdio.h>
int main()
{
    char *str;
    str = "%d\n";
    str++;
    str++;
    printf(str-2, 300);
    return 0;
}

The output of the code is 300.

I understand that Until the line before the printf statement, str is pointing to the character-%. What I need help with is understanding that why is the printf function printing 300.

Solution

  • Right before the printf, str is not pointing to the % but to the \n.

    The ++ operator increments the value of str to point to the next character in the array. Since this is done twice, it points to the \n. When you then pass str-2 to printf, it creates a pointer pointing back to the %. So printf sees the string "%d\n" which causes 300 to be printed as expected.