1. #include <stdio.h>
   int main()
   {
    int i,j;
    for (i=1;i<=5;i++)
    {
      for (j=1;j<=i;j++)
      {
       printf("*");
      }
      printf("\n");
    }
    return 0;
   }

2. #include <stdio.h>
   int main()
   {
    int i,j;
    for (i=1;i<=5;i++)
    {
      for (j=1;j<=5-i;j++)
      {
       printf(" ");
      }
      for (j=1;j<=i;j++)
      {
       printf("*");
      }
      printf("\n");
    }
    return 0;
   }

   #include <stdio.h>
   int main ()
   {
    int i,j,k;
    printf("Enter number of rows:");
    scanf("%d",&k);
    for (i=1;i<=k;i++)
    {
     for (j=1;j<=i;j++)
     {
      printf("%d",i);
     }
     printf("\n");
    }
    return 0;
   }

#include <stdio.h>
int main ()
{
 int i,j,k;
 printf("Enter number of rows:");
 scanf("%d",&k);
 for (i=k;i>=1;i--)
 {
  for (j=1;j<=i;j++)
  {
   printf("%d",j);
  }
  printf("\n");
 }
 return 0;
}

#include <stdio.h>
int main ()
{
 int i,j,k;
 printf("Enter number of rows:");
 scanf("%d",&k);
 for (i=1;i<=k;i++)
 {
  for (j=1;j<=i;j++)
  {
   printf("%d",i);
  }
  printf("\n");
 }
 return 0;
}

#include <stdio.h>
int main ()
{
 int i,j,k;
 printf("Enter number of rows:");
 scanf("%d",&k);
 for (i=k;i>=1;i--)
 {
  for (j=1;j<=i;j++)
  {
   printf("%d",i);
  }
  printf("\n");
 }
 return 0;
}

#include <stdio.h>
int main ()
{
 int i,j,k,a=1;
 printf("Enter number of rows:");
 scanf("%d",&k);
 for (i=1;i<=k;i++)
 {
  for (j=1;j<=i;j++)
  {
   printf("%d",a);
   a++;
  }
  printf("\n");
 }
 return 0;
}