bài tập cơ bản

#include<stdio.h>
#include<conio.h>
int UCLN(int a ,int b)
{
    while(a != b)
    {
        if(a > b)
            a = a - b;
        else
             b = b - a;
    }
    return a;
}
 
int BCNN(int a, int b)
{
    return a*b/UCLN(a,b);
}
void main()
{
    int a, b,i;
    for(i=1;1<=9;i++)
    {
    printf("\nNhap a: ");
    scanf("%d", &a);
    printf("\nNhap b: ");
    scanf("%d", &b);
 
    int uc = UCLN(a,b);
    printf("\n=>Uoc Chung Lon Nhat %d, %d là: %d ",a,b,uc);
    printf("\n");
 
    int bc = BCNN(a,b);
    printf("\n=>Boi Chung Nho Nhat %d, %d là: %d ",a,b,bc);
    printf("\n");
    getch();
    }
}

#include<stdio.h>
#include<conio.h>
void main()
{
	int x,i,dem=0;
	printf("Nhap so can kiem tra: ");
	scanf("%d",&x);
	    for(i=1;i<=x;i++)
		{
        if(x%i == 0)
            dem=dem+1;
		}
	if(dem==1 || dem==2)
		printf("\nSo %d la so nguyen to\n",x);
	else
		printf("\nSo %d khong phai la so nguyen to\n",x);
		
	getch();
}

#include<stdio.h>
#include<conio.h>
void main()
{
	int n,i;
	printf("Nhap so n= ");
	scanf("%d",n);
	while(n!=0)
		
		{	
			n=n/10;
			i=i+1;
		}
	printf("So chu so la i= %d",i);
	getch();
}

#include<stdio.h>
#include<conio.h>
void main()
{
	int n,m;
	printf("Nhap so can dao nguoc ");
	scanf("%d",n);
	while(n!=0)
	{
		m=m*10+n%10;
		n=n/10;
	}
	printf("So dao nguoc la %d",m);
	getch();
}