# Triangle Patterns using Loops in C

## Example 1: Program to print half pyramid using *

``````*
* *
* * *
* * * *
* * * * *``````

Code

``````#include <stdio.h>

int main()
{
int i, j, rows;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=1; i<=rows; ++i)
{
for(j=1; j<=i; ++j)
{
printf("* ");
}
printf("\n");
}
return 0;
}``````

## Example 2: Program to print half pyramid a using numbers

``````1
1 2
1 2 3
1 2 3 4
1 2 3 4 5``````

Code

``````#include <stdio.h>

int main()
{
int i, j, rows;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=1; i<=rows; ++i)
{
for(j=1; j<=i; ++j)
{
printf("%d ",j);
}
printf("\n");
}
return 0;
}``````

## Example 3: Program to print half pyramid using alphabets

``````A
B B
C C C
D D D D
E E E E E``````

Code

``````#include <stdio.h>

int main()
{
int i, j;
char input, alphabet = 'A';

printf("Enter the uppercase character you want to print in last row: ");
scanf("%c",&input);

for(i=1; i <= (input-'A'+1); ++i)
{
for(j=1;j<=i;++j)
{
printf("%c", alphabet);
}
++alphabet;

printf("\n");
}
return 0;
}``````

Programs to print inverted half pyramid using * and numbers

## Example 4: Inverted half pyramid using *

``````* * * * *
* * * *
* * *
* *
*``````

Code

``````#include <stdio.h>

int main()
{
int i, j, rows;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=rows; i>=1; --i)
{
for(j=1; j<=i; ++j)
{
printf("* ");
}
printf("\n");
}

return 0;
}``````

## Example 5: Inverted half pyramid using numbers

``````1 2 3 4 5
1 2 3 4
1 2 3
1 2
1``````

Code

``````#include <stdio.h>

int main()
{
int i, j, rows;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=rows; i>=1; --i)
{
for(j=1; j<=i; ++j)
{
printf("%d ",j);
}
printf("\n");
}

return 0;
}``````

## Example 6: Program to print full pyramid using *

``````        *
* * *
* * * * *
* * * * * * *
* * * * * * * * *``````

Code

``````#include <stdio.h>

int main()
{
int i, space, rows, k=0;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=1; i<=rows; ++i, k=0)
{
for(space=1; space<=rows-i; ++space)
{
printf("  ");
}

while(k != 2*i-1)
{
printf("* ");
++k;
}

printf("\n");
}

return 0;
}``````

## Example 7: Program to print pyramid using numbers

``````        1
2 3 2
3 4 5 4 3
4 5 6 7 6 5 4
5 6 7 8 9 8 7 6 5``````

Code

``````#include <stdio.h>

int main()
{
int i, space, rows, k=0, count = 0, count1 = 0;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=1; i<=rows; ++i)
{
for(space=1; space <= rows-i; ++space)
{
printf("  ");
++count;
}

while(k != 2*i-1)
{
if (count <= rows-1)
{
printf("%d ", i+k);
++count;
}
else
{
++count1;
printf("%d ", (i+k-2*count1));
}
++k;
}
count1 = count = k = 0;

printf("\n");
}
return 0;
}``````

## Example 8: Inverted full pyramid using *

``````* * * * * * * * *
* * * * * * *
* * * * *
* * *
*``````

Code

``````#include<stdio.h>

int main()
{
int rows, i, j, space;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=rows; i>=1; --i)
{
for(space=0; space < rows-i; ++space)
printf("  ");

for(j=i; j <= 2*i-1; ++j)
printf("* ");

for(j=0; j < i-1; ++j)
printf("* ");

printf("\n");
}

return 0;
}``````

## Example 9: Print Pascal’s triangle

``````           1
1   1
1   2   1
1   3   3    1
1  4    6   4   1
1  5   10   10  5   1``````

Code

``````#include <stdio.h>

int main()
{
int rows, coef = 1, space, i, j;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=0; i<rows; i++)
{
for(space=1; space <= rows-i; space++)
printf("  ");

for(j=0; j <= i; j++)
{
if (j==0 || i==0)
coef = 1;
else
coef = coef*(i-j+1)/j;

printf("%4d", coef);
}
printf("\n");
}

return 0;
}``````

## Example 10: Print Floyd’s Triangle.

``````1
2 3
4 5 6
7 8 9 10``````

Code

``````#include <stdio.h>

int main()
{
int rows, i, j, number= 1;

printf("Enter number of rows: ");
scanf("%d",&rows);

for(i=1; i <= rows; i++)
{
for(j=1; j <= i; ++j)
{
printf("%d ", number++);
}
printf("\n");
}

return 0;
}``````

## Example 11: Print Diamond.

``````     *
***
*****
*******
*********
*******
*****
***
*``````

Code

``````#include <stdio.h>

int main()
{
int i, j, k, n;

printf("Enter n: ");
scanf("%d",&n);

for(i=0;i<n;++i)
{
for(j=0;j<n-i;j++)
{
printf(" ");
}
for(k=0;k<=2*i;k++)
{
printf("*");
}

printf("\n");
}

n=n-1;

for(i=0;i<n;++i)
{
for(j=n-i-1;j<=n;j++)
{
printf(" ");
}
for(k=2*(n-i-1);k>=0;k--)
{
printf("*");
}

printf("\n");
}

return 0;
}``````