#include <stdio.h>
#include <stdlib.h>
 
int main(void){
   char id[6]="i0012";            // your id 
   char a[5];                     // array to hold first part of id
   int i;                         // integer variable to hold number (non-zero)
   sscanf(id,"%[^1-9]%d",a,&i);   // assign non zero number to i
   i=i+1;                         // add 1 to i 
   sprintf(id,"%s%d",a,i);        // store both a and i again into id
   printf("%s",id);
}

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