Printing triangle pattern outline using For Loop in C++
Example : 1
This is a C++ program that uses loops to print a triangular pattern of stars. The pattern is printed in a single loop. Here is an explanation of how the program works:
- The program first declares three integer variables - i, j, and n.
- The user is prompted to enter a value for n.
- The program enters a loop that iterates n times. This loop is responsible for printing the rows of the triangle.
- Within the loop, there is another loop that iterates n times. This loop is responsible for printing the columns of the triangle.
- For each element in the triangle, the program checks whether it is on the border or not. If the element is on the border (i.e., if j is equal to 1, or if i is equal to n, or if j is equal to i), then a star is printed. Otherwise, a space is printed.
- The program then exits the loop and the main() function, returning 0.
- The triangular pattern is printed to the console.
Source Code
#include<iostream>
using namespace std;
int main()
{
int i,j,n;
cout<<"\nEnter the value:";
cin>>n;
for(i=1;i<=n;i++)
{
cout<<"\n";
for(j=1;j<=n;j++)
{
if(j==1||i==n||j==i)
{
cout<<" *";
}
else
cout<<" ";
}
}
return 0;
}
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Output
Enter the value:10
*
* *
* *
* *
* *
* *
* *
* *
* *
* * * * * * * * * *
Example : 2
This is a C++ program that uses loops to print a triangular pattern of stars. The pattern is printed in a single loop. Here is an explanation of how the program works:
- The program first declares three integer variables - i, j, and n.
- The user is prompted to enter a value for n.
- The program enters a loop that iterates n times. This loop is responsible for printing the rows of the triangle.
- Within the loop, there is another loop that iterates i times. This loop is responsible for printing the spaces before the stars.
- After printing the spaces, there is another loop that iterates n-i+1 times. This loop is responsible for printing the stars.
- For each element in the triangle, the program checks whether it is on the border or not. If the element is on the border (i.e., if i is equal to 1, or if j is equal to n, or if j is equal to i), then a star is printed. Otherwise, a space is printed.
- The program then exits the loop and the main() function, returning 0.
- The triangular pattern is printed to the console.
Source Code
#include<iostream>
using namespace std;
int main()
{
int i,j,n;
cout<<"\nEnter the value:";
cin>>n;
for(i=1;i<=n;i++)
{
cout<<"\n";
for(j=1;j<=i;j++)
{
cout<<" ";
}
for(j=n;j>=i;j--)
{
if(i==1||j==n||j==i)
{
cout<<" *";
}
else
{
cout<<" ";
}
}
}
return 0;
}
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Output
Enter the value:10
* * * * * * * * * *
* *
* *
* *
* *
* *
* *
* *
* *
*
Example : 3
This is a C++ program that prints a pattern of stars in the shape of a right triangle. Here is an explanation of how the program works:
- The program first declares three integer variables - i, j, and n.
- The user is prompted to enter a value for n.
- The program enters a loop that iterates n times. This loop is responsible for printing the rows of the triangle.
- Within the loop, there is another loop that iterates n-i times. This loop is responsible for printing the spaces before the stars.
- After printing the spaces, there is another loop that iterates i times. This loop is responsible for printing the stars.
- For each element in the triangle, the program checks whether it is on the border or not. If the element is on the border (i.e., if j is equal to 1, or if i is equal to n, or if j is equal to i), then a star is printed. Otherwise, a space is printed.
- The program then exits the loop and the main() function, returning 0.
- The triangular pattern is printed to the console.
Source Code
#include<iostream>
using namespace std;
int main()
{
int i,j,n;
cout<<"\nEnter the value:";
cin>>n;
for(i=1;i<=n;i++)
{
cout<<"\n";
for(j=1;j<=(n-i);j++)
{
cout<<" ";
}
for(j=1;j<=i;j++)
{
if(j==1||i==n||j==i)
{
cout<<" *";
}
else
{
cout<<" ";
}
}
}
return 0;
}
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Output
Enter the value:10
*
* *
* *
* *
* *
* *
* *
* *
* *
* * * * * * * * * *
Example : 4
This is a C++ program that prints a pattern of stars in the shape of a pyramid. Here is an explanation of how the program works:
- The program first declares three integer variables - i, j, and n.
- The user is prompted to enter a value for n.
- The program enters a loop that iterates n times. This loop is responsible for printing the rows of the pyramid.
- Within the loop, there is another loop that iterates n-i times. This loop is responsible for printing the spaces before the stars.
- After printing the spaces, there is another loop that iterates i+1 times. This loop is responsible for printing the stars.
- For each element in the pyramid, the program checks whether it is on the border or not. If the element is on the border (i.e., if i is equal to 0, or if j is equal to 0, or if j is equal to n-i-1), then a star is printed. Otherwise, a space is printed.
- The program then exits the loop and the main() function, returning 0.
- The pyramid pattern is printed to the console.
Source Code
#include<iostream>
using namespace std;
int main()
{
int i,j,n;
cout<<"\nEnter the Limit:";
cin>>n;
for(i=0;i<n;i++)
{
for(j=0;j<n-i;j++)
{
if(i==0||j==0||j==n-i-1)
{
cout<<" *";
}
else
{
cout<<" ";
}
}
cout<<"\n";
}
return 0;
}
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Output
Enter the Limit:10
* * * * * * * * * *
* *
* *
* *
* *
* *
* *
* *
* *
*