printf dynamic length/size
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I'm trying to create a dynamic printf size for a lcd but it outputs only f=  what do i do wrong? 


    sprintf(buffer, "f=%.2f",  (d = d + 0.01)); <-- works but not dynamic 

    sprintf(buffer, "f=%.*f", 2 , (d = d + 0.01));  <-- Does not any give warning

    lcd_puts(buffer);


    _delay_ms(100);