D.ershane Solutions Ddili.org

Integers and Arithmetic Operations

  1. We can use the / operator for the division and the % operator for the remainder:
    import std.stdio;
    
    void main() {
        int first;
        write("Please enter the first number: ");
        readf(" %s", &first);
    
        int second;
        write("Please enter the second number: ");
        readf(" %s", &second);
    
        int quotient = first / second;
        int remainder = first % second;
    
        writeln(first, " = ",
                second, " * ", quotient, " + ", remainder);
    }
    
  2. We can determine whether the remainder is 0 or not with an if statement:
    import std.stdio;
    
    void main() {
        int first;
        write("Please enter the first number: ");
        readf(" %s", &first);
    
        int second;
        write("Please enter the second number: ");
        readf(" %s", &second);
    
        int quotient = first / second;
        int remainder = first % second;
    
        // We cannot call writeln up front before determining
        // whether the remainder is 0 or not. We must terminate
        // the line later with a writeln.
        write(first, " = ", second, " * ", quotient);
    
        // The remainder must be printed only if nonzero.
        if (remainder != 0) {
            write(" + ", remainder);
        }
    
        // We are now ready to terminate the line.
        writeln();
    }
    
  3. import std.stdio;
    
    void main() {
        while (true) {
            write("0: Exit, 1: Add, 2: Subtract, 3: Multiply,",
                  " 4: Divide - Please enter the operation: ");
    
            int operation;
            readf(" %s", &operation);
    
            // Let's first validate the operation
            if ((operation < 0) || (operation > 4)) {
                writeln("I don't know this operation");
                continue;
            }
    
            if (operation == 0){
                writeln("Goodbye!");
                break;
            }
    
            // If we are here, we know that we are dealing with
            // one of the four operations. Now is the time to read
            // two integers from the user:
    
            int first;
            int second;
    
            write(" First number: ");
            readf(" %s", &first);
    
            write("Second number: ");
            readf(" %s", &second);
    
            int result;
    
            if (operation == 1) {
                result = first + second;
    
            } else if (operation == 2) {
                result = first - second;
    
            } else if (operation == 3) {
                result = first * second;
    
            } else if (operation == 4) {
                result = first / second;
    
            }  else {
                writeln(
                    "There is an error! ",
                    "This condition should have never occurred.");
                break;
            }
    
            writeln("       Result: ", result);
        }
    }
    
  4. import std.stdio;
    
    void main() {
        int value = 1;
    
        while (value <= 10) {
            if (value != 7) {
                writeln(value);
            }
    
            ++value;
        }
    }