count number of characters and lines in a file
#include <iostream.h> #include <fstream.h> int main () { ifstream f1; char c; int numchars, numlines; f1.open("test"); numchars = 0; numlines = 0; f1.get(c); while (f1) { while (f1 && c != '\n') { numchars = numchars + 1; f1.get(c); } numlines = numlines + 1; f1.get(c); } cout << "The file has " << numlines << " lines and " << numchars << " characters" << endl; return(0); }
better algorithm for multiplication
#include <iostream.h> // Idea of the Russian Peasant Method (as old as 1700 B.C.) // x * n = 2x * (n/2) if n even // = x + x * (n-1) if n odd int fastmult (int x, int y) { int result; result = 0; while (y != 0) { if (y % 2 == 0) { x = 2*x; y = y/2; } else { result = result + x; y = y-1; } } return(result); } int main () { int x, y; cout << "Enter two natural numbers: "; cin >> x >> y; cout << x << " * " << y << " = " << fastmult(x,y) << endl; return(0); }
Multiplication Using Addition
#include <iostream.h> int mult (int x, int y) { int result; result = 0; while (y != 0) { result = result + x; y = y - 1; } return(result); } int main () { int x, y; cout << "Enter two natural numbers: "; cin >> x >> y; cout << x << " * " << y << " = " << mult(x,y) << endl; return(0); }
A Program to Calculate Factorial of a Number
#include <iostream.h>
int fact (int i) {
int result = 1;
while (i > 0) {
result = result * i;
i = i-1;
}
return(result);
}
int main () {
int n;
cout << "Enter a natural number: ";
cin >> n;
while (n < 0) {
cout << "Please re-enter: ";
cin >> n;
}
cout << n << "! = " << fact(n) << endl;
return(0);
}
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