Question

(Sum of digits) Make a program that reads a three-digit integer from the file "number.in" and then calculates sum of the digits and writes the result into the file"sum.out".Use the format of the sample output in the file "sumout".

Answer 1

#include<iostream>
#include <fstream>
using namespace std;

int main() {
ifstream in("sum.in");
ofstream out("sum.out");
int a,c=0;
in >> a;
while (a>0) {
c+=a;
a/=10;
}
out << c;
return 0;
}