Question

Write a c++ program that display the ff. on screen using while loop.
*
**
***
****
*****

Answer 1

Here is a program :

#include<stdio.h>
#include<stdlib.h>

int main() {
int i=1, j=1,k=1;
while(i<=5){ // i for lines (5) , in this case.
while(j<=k){ //j and k for *.
printf("*");
j += 1;
}
k += 1;
j = 1;
i += 1;
printf("\n");
}
system("pause");
}

Answer 2

what is printf("*"); ? sorry im new at c++. :)

Answer 3

You want to print :
*
**
***
****
*****

So I used printf("*") to print the * on the screen.

Answer 4

Sorry in C++, it should be like that :
#include<stdio.h>
#include<stdlib.h>
#include <iostream>

using namespace std;

int main() {

int i=1, j=1,k=1;
while(i<=5){
while(j<=k){
cout << "*";
j += 1;
}
k += 1;
j = 1;
i += 1;
cout << "\n";
}
system("pause");
}
use cout instead of printf.

Answer 5

yes. im using c++. let me try your code. thanks :)

Answer 6

Ok yes, Welcome.

Answer 7

Hello ktobah.. the code worked and its great thanks. but i cant understand how it works. can you explain and trace it for me?

Answer 8

Yes sure, here what I did :

int main() {
// Here declaration of variables;
int i=1, j=1,k=1;

// We want to print 5 lines so for that I used 5, so remember i is for lines.
while(i<=5){

// Here I used k as the number of maximum "*", and I increment "j" until j>k, so when j<=k , I print "*"
while(j<=k){
cout << "*";
j += 1;
}

//When I print the "*" of the first line, I increment k, example :
// For the first line we have i=1 (first line), and k=1 (the number of "*")
// for the first line, so we initialize j with 1, and we start the loop
// i = 1, is (i=1) <= (5) --> yes, so enter the loop;
// (j=1) <= (k=1) --> yes, so enter the loop;
// print "*";
// j = 2 , we increment j
// (j=2) <= (k=1) --> No, so exit the loop;
// Now increment k to 2, means two "*" for the second line.
k += 1;
// Reset j to 1, so we start from the beginning of the second line
j = 1;
// And increment i to 2, means we will go to the 2nd line.
i += 1;
// This instruction means return to a new line; for example we print "*"
// of the first line, so after (cout << "\n"), we will go to the 2nd line
// and print "**".
cout << "\n";
}

And so on.... until you print all the 5 lines. Good luck.

Answer 9

Thank you very much! you're the best! :))

Answer 10

haha it's ok, you are welcome.

Answer 11

How about this figure in while loop and do while:
*
* *
* * *
* * * *
* * * * *

Answer 12

Hello, well I will solve it with the while loop, and you make it with the do while loop:

#include<stdio.h>
#include<stdlib.h>

main()
{
/* Declare our variables, row for the number of lines
'J' to print the ' ' speaces and the '*'
'temp' is used as the number of spaces for each line.
*/
int i, j, temp;
//intialize temp with 1
temp = 5;
//intialize i with 1, means the 1st line.
i = 1;
while (i <= 5){
//intialize j with 1, means the Number of ' ' and '*'.
j = 1 ;
// Temp is the number of spaces, at first it's 5
while (j < temp){
// Print the space
printf(" ");
// And increment j with 1
j++;
}
/*After finishing the 5 spaces for the 1st line, we
should minus 1 from temp, that mean for the 2nd
line we will have 4 spaces, and so on...
*/
temp--;
// Now time to print the '*', so we reintialize j to 1
j = 1 ;
/* We take j<2*i-1 because we are going to print the
double number, example if i=2 then j <3 that
means we will print 3 '*' in the 2nd line*/
while(j <= 2*i - 1){
printf("*");
j++;
}
/* After finishing with a line, we should
return to a new line*/
printf("\n");
// And go to the next line.
i++;
}
system("pause");
return 0;
}

Good luck, just delete the comments from the program and it will looks simple and little!

Answer 13

Hello @ktobah i reviewed your reply, i understand your explanation but when i do your code suddenly went wrong. i don't know how to trace the error. here is what i typed.


// triangle (whilw loop).cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
int i,j,temp;

temp = 5;
i = 1;

while (i <= 5)
{
j = 1;
{
while (j < temp)
{
cout<<" ";
j=1;
}

temp--;
j = 1;

while(j <= 2*i - 1)
{
cout<<" ";
j++;
}

cout<<"\n";
i++;

}


system("pause");
return 0;
}

Answer 14

Well you have a problem in the "{}", this is what I wrote :

while (i <= 5){
j = 1 ;
while (j < temp){
printf(" ");
j++;
}
temp--;
j = 1 ;
while(j <= 2*i - 1){
printf("*");
j++;
}
printf("\n");
i++;
}

You can notice that both "while(j < temp)" and "while(j < = 2*i -1)" are inside the big loop "while (i <= 5). That's your error. Good luck.