Lesson 2

 C++ Lesson 2

 

Learning Objectives:

1.      How to use for loop?

2.      Single loop

3.      How to trace the value of variable?

Preview objectives

1.      Nested Loop (double loop)

 

Exercise 2-1: observe the output

#include <iostream>

using namespace std;

int main() {

int i;

i=1;

for (i;i<4;i=i+1){

    cout<<"*";

}

    return 0;

}

Exercise 2-2: observe the output

#include <iostream>

using namespace std;

int main() {

int i;

i=1;

for (i;i<4;i=i+1){

    cout<<"*"<<"\n";

}

    return 0;

}

 

<<作業2-1>>

讓使用者自行輸入次數，然後輸出相應數目的 * 。

輸出如下圖:

 

Exercise 2-3: observe the output

#include <iostream>

using namespace std;

int main() {

int i;

i=1;

for (i;i<=50;i=i+1){

    cout<<i<<" ";

}

    return 0;

}

<<Assignment 2-2>>

Output the numbers from 10 to 40 as follow:

 

 

<<Assignment 2-3>>

Output the even numbers from 1 to 50 as follow:

 

 

<<Assignment 2-4>

Let the user enter a smaller number first, and then a greater number and then output all the integers(整數) between these two numbers. The output is as follow:

 

 

Preview Exercise:

#include <iostream>

using namespace std;

int main() {

int i,j;

int total;

int length;

i=1;

j=1;

cout<<"enter the number of digits per row: ";

cin>>length;

cout<<"enter the total numbers: ";

cin>>total;

for (i;i<=total;i++){

    for (j;j<=length;j++){

        cout<<i<<",";

        i=i+1;

    }

    i=i-1;

    cout<<"\n";

    j=1;

}

}