second

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

third

#include <stdio.h>

int main()
{
    int i, j;
    for (i = 1; i <= 5; i++)
    {
        for (j = 1; j <= i; j++)
        {
            printf("%c ", 'A' + j - 1);
        }
        printf("\n");
    }
    return 0;
}

fourth

#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("%d", j);
        }
        for (j = i - 1; j >= 1; j--)
        {
            printf("%d", j);
        }
        printf("\n");
    }
    return 0;
}