Gregorian Calendar- Identify the day based on Year

I need help with this code whose purpose is written in the comments. When I enter the year, the code ends and nothing is printed. Can someone guide me on my error.

#include<stdio.h>

int main() {

    /*According to the Gregorian calendar, it was Monday on the
date 01/01/1900. If any year is input through the keyboard
write a program to find out what is the day on 1st January of
this year.*/

    int year, diff;
    int n = 1;
    int m;
    printf("Year: ");
    scanf("%d", year);
    diff = year - 1900;
    n += (diff / 4)*2 + (diff - (diff/4))*1;
    m = (n % 7);
    switch(m) {
        case 1: 
            printf("Monday\n");
            break;
        case 2: 
            printf("Tuesday");
            break;
        case 3: 
            printf("Wednesday");
            break;
        case 4: 
            printf("Thurday");
            break;
        case 5: 
            printf("Friday");
            break;
        case 6: 
            printf("Saturday");
            break;
        case 7: 
            printf("Sunday");
            break;
        default:
            printf("Error");
            break;
    }   
}

Use integer pointer instead of int year variable
eg :int* year;