desired code:
your textcall_func_init(){
your textINVAR3_sah = INIT_VAL;
your text}
your textcall_func_mgm(){
your textINVAR3_INCR = INVAR3 - INVAR3_sah;
your textINVAR3_sah = INVAR3;
your text}
I am a beginner and this is just a task my instructor gave me.