C program to find factorial by using pointers and recursion

#include<stdio.h>
#include<conio.h>
int fact(int);
main()
{
int n;
printf("enter value of fact to be find; \n");
scanf("%d",&n);
fact(n);
printf("%d factorial is %d",n,fact(n));
}
int fact(int m)
{
int f;
if(m==1)
return(1);
else
f=m*fact(m-1);
return(f);
}

C program to sort elements in an array:

#include<stdio.h>
#include<conio.h>
main()
{
int i,j,t,arr[]={1,2,4,3,6,5};
for(i=0;i<6;i++)
{
for(j=i+1;j<6;j++)
{
if(arr[i]>arr[j])
{
t=arr[i];
arr[i]=arr[j];
arr[j]=t;
      }
}
}
for(i=0;i<6;i++)
printf("%d ",arr[i]);
getch();
}

C program to concatinate two strings without using library functions:

#include<stdio.h>

#include<string.h>
void  concat(char str1[],char str2[])
{
int i,j;
i=strlen(str1);
for(j=0;str2[j]!='\0';i++,j++)
{
str1[i]=str2[j];
    }
    str1[i]='\0';
 
}
main()
{
char str1[50],str2[30];
printf("enter the strings:");
gets(str1);
gets(str2);
concat(str1,str2);
printf("concat string is %s",str1);
}