На сколько дней студенту хватит стипендии S, если он тратит N руб. в день и его расходы увеличиваются в X раз?

~/cpp/other/stip $ cat stip01.c 
#include <stdio.h>
 
int main(void){
    double s, n, x;
    int days;
 
    printf("S = ");
    scanf("%lf", &s);
    printf("N = ");
    scanf("%lf", &n);
    printf("X = ");
    scanf("%lf", &x);
 
    for ( days = 0; s - n >= 0; ++days, n *= x )
        s -= n;
    printf("Enough for %d days, and %.2f money left.\n", days, s);
 
    return 0;
}
 
~/cpp/other/stip $ gcc -o stip01 stip01.c 
~/cpp/other/stip $ cat stip02.cpp 
#include <iostream>
using namespace std;
int main()
{
double s,n,x;
int c=0;
cout <<"S=";
cin>>s;
cout<<"N=";
cin>>n;
cout<<"x=";
cin>>x;
while (s>=n)
{
c++;
s-=n;
n*=x;
}
cout<<"Stipendii xvatit na:"<<c<<"dney\nOstaetsya:"<<s<<endl;
return 0;
}
~/cpp/other/stip $ g++ -o stip02 stip02.cpp 
~/cpp/other/stip $ cat stip03.c 
#include <stdio.h>
 
int main(void){
    double s, n, x;
    int days;
 
    printf("S = ");
    scanf("%lf", &s);
    printf("N = ");
    scanf("%lf", &n);
    printf("X = ");
    scanf("%lf", &x);
 
    printf("\nDay #        Spent      Remains\n----------------------------------------\n");
    for ( days = 0; s - n >= 0; ++days, n *= x ){
        s -= n;
        printf("%5d   %10.2f   %10.2f\n", days + 1, n, s);
    }
 
    printf("\n----------------------------------------\nEnough for %d days, and %.2f money left.\n", days, s);
 
    return 0;
}
~/cpp/other/stip $ gcc -o stip03 stip03.c 
~/cpp/other/stip $ ./stip01
S = 150000
N = 5000
X = 2
Enough for 4 days, and 75000.00 money left.
~/cpp/other/stip $ ./stip02
S=150000
N=5000
x=2
Stipendii xvatit na:4dney
Ostaetsya:75000
~/cpp/other/stip $ ./stip03
S = 150000
N = 5000
X = 2
 
Day #        Spent      Remains
----------------------------------------
    1      5000.00    145000.00
    2     10000.00    135000.00
    3     20000.00    115000.00
    4     40000.00     75000.00
 
----------------------------------------
Enough for 4 days, and 75000.00 money left.
~/cpp/other/stip $