Calculation s=1+12+123+1234+12345 C language

#define N 5
#include <stdio.h>
int main(){
    int t = 0,  s = 0 , i;
    for (i = 1; i <= N; i++)    {
        t = i + t * 10 ;
        s += t;
    }
    printf("s=%d\n", s);
    return 0;
}