Creating patterns in Java with nested loops
Nested Loops- Java
v Nested
loop means a loop within a loop.
v It
refers to a repeated iteration in a given number within an iteration.
v To
print different elements we print column value or the variable used for column.
v To
print the same elements we will print the value of the row or the variable used for a row.
v Row
means line. Column means element.
Given
below is a basic program written for nested 'for' loops.
To print:
@@@@
@@@@
@@@@
@@@@
public
class Pattern
{
public static void main(String[] args)
{
int r,c;
for(r=1;r<=4;r++)
{
for(c=1;c<=4;c++)
{
System.out.print("@");
}
System.out.println();
}
}
}
Triangle
Questions
To print:
1
12
123
public
class Pattern
{
public static void main(String[] args)
{
int r,c;
for(r=1;r<=3;r++)
{
for(c=1;c<=r;c++)
{
System.out.print(c);
}
System.out.println();
}
}
}
To print:
1
22
333
public
class Pattern
{
public static void main(String[] args)
{
int r,c;
for(r=1;r<=3;r++)
{
for(c=1;c<=r;c++)
{
System.out.print(r);
}
System.out.println();
}
}
}
To print:
1
23
456
public
class Pattern
{
public static void main(String[] args)
{
int r,c, i;
i=1;
for(r=1;r<=3;r++)
{
for(c=1;c<=r;c++)
{
System.out.print(i);
i++;
}
System.out.println();
}
}
}
To print:
1
12
123
public
class Pattern
{
public static void main(String[] args)
{
int r,c,i;
for(r=1;r<=3;r++)
{
for(c=1,i=1;c<=r;c++,i++)
{
System.out.print(i);
}
System.out.println();
}
}
}
To print:
654
32
1
public
class Pattern
{
public static void main(String[] args)
{
int r,c,i=6;
for(r=1;r<=3;r++)
{
for(c=3;c>=r;c--)
{
System.out.print(i);
i--;
}
System.out.println();
}
}
}
To print:
321
32
1
public
class Pattern
{
public static void main(String[] args)
{
int r,c;
for(r=1;r<=3;r++)
{
for(c=3;c>=r;c--)
{
System.out.print(c);
}
System.out.println();
}
}
}
Right-angled triangles
For this, we need to use
two variables for column
We are using the c1 variable
to create space before printing the elements.
We are using the c2 variable
to print the elements of the program.
To print:
---1
--12
-123
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2;
for(r=1;r<=3;r++)
{
for(c1=3;c1>=r;c1--)
{
System.out.print("
");
}
for(c2=1;c2<=r;c2++)
{
System.out.print(c2);
}
System.out.println();
}
}
}
To print:
---1
--22
-333
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2;
for(r=1;r<=3;r++)
{
for(c1=3;c1>=r;c1--)
{
System.out.print("
");
}
for(c2=1;c2<=r;c2++)
{
System.out.print(r);
}
System.out.println();
}
}
}
To print:
-321
--21
---1
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2;
for(r=3;r>=1;r--)
{
for(c1=3;c1>=r;c1--)
{
System.out.print("
");
}
for(c2=r;c2>=1;c2--)
{
System.out.print(c2);
}
System.out.println();
}
}
}
To print:
-123
--23
---3
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=0;
for(r=1;r<=3;r++)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3,i=r;c2>=r;c2--)//I is
starting with row value
{
System.out.print(i);i++;
}
System.out.println();
}
}
}
To print:
---3
--23
-123
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=0;
for(r=3;r>=1;r--)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3,i=r;c2>=r;c2--)
{
System.out.print(i);i++;
}
System.out.println();
}
}
}
To print:
---A
--BA
-CBA
public
class Pattern
{
public static void main(String[] args)
{
char r,c1,c2,i=0;
for(r='A';r<='C';r++)//A,BA,CBA
{
for(c1='C';c1>=r;c1--)
{
System.out.print("
");
}
for(c2='A',i=r;c2<=r;c2++)
{
System.out.print(i);i--;
}
System.out.println();
}
}
}
To print:
4321
432
43
4
public
class pattern_0
{
public static void main(String []args)
{
int i=4;
for(int r=1;r<=4;r++)
{i=4;
for(int c=4;c>=r;c--)
{
System.out.print(i--);
}
System.out.println();
}
}
}
To print:
---1
--12
-123
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=0;
for(r=1;r<=3;r++)
{
for(c1=3;c1>=r;c1--)
{
System.out.print("
");
}
for(c2=1,i=r;c2<=r;c2++)
{
System.out.print(c2);
}
System.out.println();
}
}
}
To print:
---1
--21
-321
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=0;
for(r=1;r<=3;r++)
{
for(c1=3;c1>=r;c1--)
{
System.out.print("
");
}
for(c2=1,i=r;c2<=r;c2++)
{
System.out.print(i);i--;
}
System.out.println();
}
}
}
To print:
---A
--BB
-CCC
public
class Pattern
{
public static void main(String[] args)
{
char r,c1,c2,i=0;
for(r='A';r<='C';r++)
{
for(c1='C';c1>=r;c1--)
{
System.out.print("
");
}
for(c2='A';c2<=r;c2++)
{
System.out.print(r);
}
System.out.println();
}
}
}
To print:
****
***
**
*
public
class pattern_0
{
public static void main(String []args)
{
int i=4;
for(int r=1;r<=4;r++)
{i=4;
for(int c=4;c>=r;c--)
{
System.out.print("*
");//can print with or without the //space as per your choice or
atq
}
System.out.println();
}
}
}
To print:
1234
1234
1234
public
class Pattern
{
public static void main(String[] args)
{
for(int r=1;r<=3;r++)
{
for(int c=1;c<=r;c++)
{
System.out.print(c);
}
System.out.println();
}
}
}
To print:
-111
- -22
---
3
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=1;
for(r=1;r<=3;r++)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3;c2>=r;c2--)
{
System.out.print(r);
}
System.out.println();
}
}
}
To print:
123
45
6
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=1;
for(r=1;r<=3;r++)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3;c2>=r;c2--)
{
System.out.print(i++);
}
System.out.println();
}
}
}
To print;
234
56
7
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=1;
for(r=1;r<=3;r++)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3;c2>=r;c2--)
{
System.out.print(++i);
}
System.out.println();
}
}
}
To print:
123
12
1
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=1;
for(r=1;r<=3;r++)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3;c2>=r;c2--)
{
System.out.print(++i);
}
System.out.println();
}
}
}
To print:
4
34
234
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=1;
for(r=3;r>=1;r--)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3,i=r;c2>=r;c2--)
{
System.out.print(++i);
}
System.out.println();
}
}
}
To print:
2
34
567
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=1;
for(r=3;r>=1;r--)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3;c2>=r;c2--)
{
System.out.print(++i);
}
System.out.println();
}
}
}
To print:
1
23
456
public
class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=1;
for(r=3;r>=1;r--)
{
for(c1=1;c1<=r;c1++)
{
System.out.print("
");
}
for(c2=3;c2>=r;c2--)
{
System.out.print(i++);
}
System.out.println();
}
}
}
To print:
AAAA
BBBB
CCCC
public
class pattern_0
{
public static void main(String []args)
{
for(char r='A';r<='C';r++)
{
for(int c=1;c<=4;c++)
{
System.out.print(r);
}
System.out.println();
}
}
}
To print:
ABCD
EFGH
IJKL
public
class pattern_0
{
public static void main(String []args)
{
char i='A';
for(char r='A';r<='C';r++)
{
for(int c=1;c<=4;c++)
{
System.out.print(i++);
}
System.out.println();
}
}
}
To print:
C
BC
ABC
public
class Pattern
{
public static void main(String[] args)
{
char r,c1,c2,i=0;
for(r='C';r>='A';r--)
{
for(c1='A';c1<=r;c1++)
{
System.out.print("
");
}
for(c2='C',i=r;c2>=r;c2--)
{
System.out.print(i);i++;
}
System.out.println();
}
}
}
To print:
*
*#
*#*
*#*#
*#*#*
public
class Pattern
{
public static void main(String[] args)
{
int r,c;
for(r=1;r<=5;r++)
{
for(c=1;c<=r;c++)
{
if(c%2==0)
{
System.out.print("#");
}
else
{
System.out.print("*");
}
}
System.out.println();
}
}
}
To print:
54321
5432
543
54
5
public
class Pattern
{
public static void main(String[] args)
{
int r,c;
for(r=1;r<=5;r++)
{
for(c=5;c>=r;c--)
{
System.out.print(c);
}
System.out.println();
}
}
}
To print:
13579
1357
135
13
1
public
class Pattern
{
public static void main(String[] args)
{
int r,c,i;
for(r=5;r>=1;r--)
{
for(c=1,i=1;c<=r;c++,i+=2)//in
the middle only one statem
{
System.out.print(i);
}
System.out.println();
}
}
}
To print:
12345
1234
123
12
1
public
class Pattern
{
public static void main(String[] args)
{
int r,c;
for(r=5;r>=1;r--)
{
for(c=1;c<=r;c++)//in the middle
only one statem
{
System.out.print(c);
}
System.out.println();
}
}
}
To
print:
A
BC
CDE
public
class Pattern
{
public static void main(String[] args)
{
char r,c1,c2,i=0;
for(r='A';r<='C';r++)
{
for(c1='C';c1>=r;c1--)
{
System.out.print("
");
}
for(c2='A',i=r;c2<=r;c2++)
{
System.out.print(i);i++;
}
System.out.println();
}
}
}
To print:
1
23
345
public class Pattern
{
public static void main(String[] args)
{
int r,c1,c2,i=0;
for(r=1;r<=3;r++)
{
for(c1=3;c1>=r;c1--)
{
System.out.print("
");
}
for(c2=1,i=r;c2<=r;c2++)
{
System.out.print(i);i++;
}
System.out.println();
}
}
}
To print:
9 9 9 9 9
7 7 7 7 7
5 5 5 5 5
3 3 3 3 3
1 1 1 1 1
public
class Pattern_0
{
public static void main(String[] args)
{
for(int r=9;r>=1;r-=2)
{
for(int c=1;c<=5;c++)
{
System.out.print(r+"
");
}
System.out.println();
}
}
}
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