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warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘int *’ [-Wformat=]

+1 vote
asked Nov 11, 2020 by Gustavo Zuffellato (130 points)
i'm writing a program in c for school where the user write a number and the program say if it's a prime number or not

#include <stdio.h>
int main (){
    int n, divisore;
    printf("dimmi un numero e ti dirò se è primo o no\n");
    printf("inserisci il numero: ");
    while(divisore>n || n%divisore!=0){
    if(n%divisore==0 && divisore!=n){
        printf("%d non è un numero primo",& n);
        printf("%d è un numero primo",& n);


the problem is in the last two printf but i don't understand what's wrong

1 Answer

0 votes
answered Nov 11, 2020 by xDELLx (7,630 points)

The warning says it all. %d is expecting an int but you are passing an address to int (int *), ie '&n'

To correct it write printf as below:

 printf("%d non è un numero primo",n);

Also the logic of your code seems off.The loop runs infinitely, check the condition divisore>n, is it required or needs correction.

  while(divisore>n || n%divisore!=0){

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