C: for loop int initial declaration

Can someone elaborate on the following gcc error?

$ gcc -o Ctutorial/temptable.out temptable.c 
temptable.c: In function ‘main’:
temptable.c:5: error: ‘for’ loop initial declaration used outside C99 mode

temptable.c:

...
/* print Fahrenheit-Celsius Table */
main()
{
    for(int i = 0; i <= 300; i += 20)
    {
        printf("F=%d C=%d\n",i, (i-32) / 9);        
    }
}

P.S: I vaguely recall that int i should be declared before a for loop. I should state that I am looking for an answer that gives a historical context of C standard.

C: for loop int initial declaration

2 Answers