Tabmult

What's Tabmult

Tabmult is a function that displays a number's multiplication table.

The parameter will always be a strictly positive number that fits in an int. Said number multiplied by 9 will also fit in an int.

PrintStr function

We define a function called PrintStr that will allow us to print a string we will give to it.

func PrintStr(s string) {
  for i := 0; i < len(s); i++ {
    z01.PrintRune(rune(s[i]))
  }
  z01.PrintRune('\n')
}

Tabmult step by step

First step

If the number of arguments is different from 2 (number + name of the file), then we end the programm.

if len(os.Args) != 2 {
    return
}

Second step

We then store into a new variable the convertion of our argument to an int to be able to apply multiplications to it.

number, err := strconv.Atoi(os.Args[1])
    if err != nil {
        return
    }

Also we check for error, if for example the argument given isn't an int.

Third step

We make a loop that will start at 1 and end at 9. That index will be the number that will multiply our converted os.Args[1].

for i := 1; i < 10; i++ {
}  

Fourth and final step

We only need now to print our lines using our PrintStr function.
We have to keep in mind that our function only print strings, so we will have to convert the ints into strings inside the function.

PrintStr(strconv.Itoa(i) + " x " + os.Args[1] + " = " + strconv.Itoa(i * number))
z01.PrintRune('\n')

Note that we can add strings to eachothers and it will work like the append function works on arrays.

Full code

package main

import (
    "os"
    "strconv"

    "github.com/01-edu/z01"
)

func PrintStr(s string) {
    for i := 0; i < len(s); i++ {
        z01.PrintRune(rune(s[i]))
    }
}

func TabMult() {
    if len(os.Args) != 2 {
        return
    }
    number, err := strconv.Atoi(os.Args[1])
    if err != nil {
        return
    }
    for i := 1; i < 10; i++ {
        PrintStr(strconv.Itoa(i) + " x " + os.Args[1] + " = ")
        PrintStr(strconv.Itoa(i * number))
        z01.PrintRune('\n')
    }
}