Dấu sao tam giác vuông
#include"stdio.h"
#include"conio.h"
#include"math.h"
void main()
{
clrscr();
int n,i,j,k;
printf ("\nBan hay nhap so nguyen duong n
sao cho 0<n<25");
printf ("\nn=");scanf ("%d",&n);
for (i=1;i<=n;i++)
{
for (j=1;j<=i;j++)
printf ("*");
printf ("\n");
}
getch();
}
đọc số bằng chữ
#include"conio.h"
#include"stdio.h"
#include"math.h"
void main()
{
clrscr();
int a,b,c,n,k;
k=0;
do
{
printf ("\nBan hay nhap so n sao cho

switch(b)
{
case 1:printf ("muoi ");break;
case 2:printf ("hai ");break;
case 3:printf ("ba "); break;
case 4:printf ("bon ");break;
case 5:printf ("nam ");break;
case 6:printf ("sau ");break;
case 7:printf ("bay ");break;
case 8:printf ("tam ");break;
case 9:printf ("chin ");break;
default:break;
}
}
if (b>1) printf ("muoi ");
else printf (" ");
switch(a)
{
case 0:printf (" ");break;
case 2:printf ("hai ");break;
case 3:printf ("ba "); break;
case 4:printf ("bon ");break;
case 5:printf ("nam ");break;
case 6:printf ("sau ");break;
case 7:printf ("bay ");break;
case 8:printf ("tam ");break;
case 9:printf ("chin ");break;
}
getch();
}

clrscr();
int n,i,j,k;
printf ("\nBan hay nhap so nguyen duong n
sao cho 0<n<25");
printf ("\nn=");scanf ("%d",&n);
for (i=1;i<=n;i++)
{
for (j=1;j<=n-i;j++)
printf (" ");
for (j=1;j<=2*i-1;j++)
printf ("*");
printf ("\n");
}
getch();
}
dấu sao tam giác vuông_bài 8
#include"stdio.h"
#include"conio.h"
#include"math.h"
void main()
{
clrscr();
int n,i,j,k;
printf ("\nBan hay nhap so nguyen duong n
sao cho 0<n<25");
printf ("\nn=");scanf ("%d",&n);
for (i=1;i<=n;i++)
{
for (j=1;j<=n-i;j++)
printf (" ");

nao",n);
getch();
}
viết 00 đến 99
#include"conio.h"
#include"stdio.h"
#include"math.h"
void main()
{
clrscr();
int i,j;
for (i=0;i<=9;i++)
{
for (j=0;j<=9;j++)
printf ("%7d",i*10+j);
printf ("\n");
}
getch();
}
nhập số nguyên dương không quá 4 số
#include"stdio.h"
#include"conio.h"
2
#include"math.h"
void main()/*Luu y n la kieu nguyen nen khi
nhap n khong qua 32767*/
{
clrscr();
int k,n,m,d,t;
k=0;

printf ("\nn=");scanf ("%d",&n);
for (i=1;i<=n;i++)
{
for (j=1;j<=n-i;j++)
printf (" ");
for (j=1;j<=i;j++)
printf ("%d",j);
for (j=1;j<=i-1;j++) printf ("%d",i-j);
printf ("\n");
}
getch();
}
các số xuất hiện hơn 1 lần 1 dãy
#include"conio.h"
#include"stdio.h"
#include"math.h"
void main()
{
clrscr();
int a[50],n,i,j,tg,k;
printf ("\nBan hay nhap n");
printf ("\nn=");scanf ("%d",&n);
printf ("\nNhap cac phan tu trong day:");
for (i=1;i<=n;i++)
{
printf ("\nPhan tu thu %d la ",i);scanf
("%d",&a[i]);
}
for (i=1;i<n;i++)
for (j=i+1;j<=n;j++)

printf ("Ban hay nhap chieu dai 3 canh cua tam
giac a,b,c");
printf ("\na=");scanf ("%f",&a);
printf ("\nb=");scanf ("%f",&b);
printf ("\nc=");scanf ("%f",&c);
3
if ((a+b>c)&&(b+c>a)&&(c+a>b))
{
p=(a+b+c)/2;
dientich=sqrt(p*(p-a)*(p-b)*(p-c));
printf ("\nDien tich tam giac la %f",dientich);
}
else printf ("\na,b,c khong phai 3 canh cua 1
tam giac");
getch();
}
pt bậc 2
#include"math.h"
#include"conio.h"
#include"stdio.h"
void main() /*Giai phuong trinh bac 2*/
{
clrscr();
float a,b,c,denta;
printf ("Ban hay nhap 3 so a,b,c");
printf ("\na=");scanf ("%f",&a);
printf ("\nb=");scanf ("%f",&b);
printf ("\nc=");scanf ("%f",&c);
denta=b*b-4*a*c;
if (denta<0) printf ("\nPhuong trinh vo

sqrt(denta))/2*a)),(sqrt((-b-sqrt(denta))/2*a)));
getch();
}
tìm số lớn nhất trong 3 số
#include"math.h"
#include"conio.h"
#include"stdio.h"
void main() /*Tim so lon nhat trong 3 so*/
{
clrscr();
float a,b,c,max;
printf ("Ban hay nhap 3 so a,b,c");
printf ("\na=");scanf ("%f",&a);
printf ("\nb=");scanf ("%f",&b);
printf ("\nc=");scanf ("%f",&c);
if (a>b) max=a;
else max=b;
if (max<c) max=c;
printf ("\nSo lon nhat trong 3 so la %f",max);
getch();
}
bảng cửu chương
#include"conio.h"
#include"stdio.h"
#include"math.h"
void main()
{
clrscr();
int i,j;
for (i=1;i<=10;i++)

getch();
}
mức tăng dân số hàng năm
#include"conio.h"
#include"stdio.h"
#include"math.h"
void main()
{
clrscr();
int x,z,t;
float y;
printf ("\nBan hay nhap x,y,z");
printf ("\nDan so the gioi hien tai la ");scanf
("%d",&x);
printf ("\nMuc tang dan so hang nam la
");scanf ("%f",&y);
printf ("\nDan so the gioi trong tuong lai
");scanf ("%d",&z);
t=0;
while (x<z)
{
x=x+x*(float)(y)/100;
t++;
}
printf ("\nSo nam de dan so vuot qua %d
nguoi la %d ",z,t);
getch();
}
in ra n ở dạng nhị phân
#include"stdio.h"

printf ("Ban hay nhap n");
printf ("\nn=");scanf ("%d",&n);
m=n;
i=0;
while (m!=0)
{
d=m%16;
m=m/16;
i=i+1;
a[i]=d;
}
printf ("\n%d bieu dien duoi dang co so 16
la:",n);
for (j=i;j>=1;j )
switch (a[j])
{
case 10:printf ("A");break;
case 11:printf ("B");break;
case 12:printf ("C");break;
case 13:printf ("D");break;
case 14:printf ("E");break;
case 15:printf ("F");break;
default:printf ("%d",a[j]);
}
getch();
}
5
in ra màn hình những số nguyên tố < n
#include"conio.h"
#include"math.h"

printf ("\nn=");scanf ("%d",&n);
for (i=1;i<n;i++)
{
t=0;
for (j=1;j<=i;j++)
if (i%j==0) t=t+j;
if (t/i==2) printf ("\nSo hoan hao nho hon n la
%d",i);
}
getch();
}
in ra màn hình giá trị biểu thức f(x,y)
#include"conio.h"
#include"math.h"
#include"stdio.h"
void main()
{
clrscr();
float x,y,f;
printf ("\nBan hay nhap x,y");
printf ("\nx=");scanf ("%f",&x);
printf ("\ny=");scanf ("%f",&y);
if (x<y) f=2*x-y*y+2;
if (x==y) f=exp(x*y-y)+sin(x-3*y);
if (x>y) f=log(x*x*x-2*x*y)
+sqrt(x*x+2*y*y);
printf ("\nGia tri bieu thuc la %f",f);
getch();
}
S=1

void main()
{
clrscr();
float x,f,a,b;
printf ("\nBan hay nhap x");
printf ("\nx=");scanf ("%f",&x);
if (x<1) a=abs(x*x-3*x+2)+sin(2*x-1);
else if (1<=x<=2) a=sqrt(x*x-1)-log(x-
1)/log(3);
else a=exp(2*x+3)-pow(x,5)+3;
b=pow(x,5)-3*x*x+2;
f=3*a*a*b-abs(a-b)+exp(2*a+1);
printf ("\nGia tri bieu thuc la: %f",f);
getch();
}
6
!
1
)1 (
!3
1
!2
1
!1
1
1
n
s
n +
−++−=

printf ("\nc=");scanf ("%f",&c);
if
((a>0)&&(b>0)&&(c>0)&&(a+b>c)&&(b+c>
a)&&(c+a>b)) k=1;
if (k==0) printf ("\Ban hay nhap lai a,b,c");
}
while (k==0);
printf ("\nDo dai 3 canh cua tam giac ban vua
nhap la \na=%f\nb=%f\nc=%f",a,b,c);
getch();
}
chu vi, diện tích, đường cao tam giác
#include"stdio.h"
#include"conio.h"
#include"math.h"
void main()
{
clrscr();
float a,b,c,p,s;
int k;
k=0;
do
{
printf ("\nBan hay nhap a,b,c la do dai 3 canh
1 tam giac");
printf ("\na=");scanf ("%f",&a);
printf ("\nb=");scanf ("%f",&b);
printf ("\nc=");scanf ("%f",&c);
if
(a>0)&&(b>0)&&(c>0)&&(a+b>c)&&(b+c>a

int i;
printf ("\nDay A ban vua nhap la: ");
for (i=1;i<=n;i++) printf ("%d ",a[i]);
printf ("\n");
}
void soam(int a[50],int n)
{
int i,k,t;
k=0;
for (i=1;i<=n;i++)
7
if (a[i]<0)
{
k=1;
t=i;
break;
}
if (k==0) printf ("\nDay A vua nhap khong co
so am");
else printf ("\nVi tri so am dau tien trong day
A tu trai sang phai la %d",t);
}
void slt2(int a[50],int n)
{
int i,j,tg;
for (i=1;i<n;i++)
for (j=i+1;j<=n;j++)
{
if (a[i]>a[j])
{

{
if (a[i]*a[j]<0) k=1;
else k=0;
}
if (k==1) printf ("\nDay A la day dan dau");
else printf ("\nDay A khong phai day dan
dau");
}
void tbc(int a[50],int n)
{
int i,t;
float tbc;
t=0;
for (i=1;i<=n;i++)
t=t+a[i];
tbc=(float)(t)/n;
printf ("\nTrung binh cong cac so trong day A
la %f",tbc);
}
void so(int a[50],int n)
{
int i,j,k;
k=0;
printf ("\nCac so trong day xuat hien nhieu
hon mot lan la: ");
for (i=1;i<n;i++)
{
for (j=i+1;j<=n;j++)
if (a[i]==a[j])
{

8
nhap(a,&n);
hienthi(a,n);
soam(a,n);
slt2(a,n);
xapxep(a,n);
kt(a,n);
tbc(a,n);
so(a,n);
snt(a,n);
getch();
}
mảng 2 chiều
#include<stdio.h>
#include<conio.h>
/*nhap mang hai chieu*/
void nhap(int A[10][10],int*n)
{int i,j,tg;
printf("nhap kich thuoc ma tran
n=");scanf("%d",n );
for (i=1;i<=*n;i++)
for (j=1;j<=*n;j++)
{
printf("nhap cac phan tu hang %d cot
%d=",i,j);
scanf("%d",&tg);
A[i][j]=tg;
}
}
/*hien thi A ra man hinh*/

{
printf("\n cac phan tu tren hang %d",i);
for (j=1;j<=n;j++)
printf ("%3d",A[i][j]);
printf("\n");
}
}}
/*xap xep cac ham theo
thu tu tang dan*/
void xapxephang(int A[10][10],int n)
{
int i,j,k,tg;
printf ("nhap hang k=");
scanf ("%d",k);
for (i=1;i<=n;i++)
for (j=1;j<=n;j++)
if (A[k][i]<A[k][j])
{
A[k][i]=A[k][j];
A[k][j]=tg;
}
printf ("ma tran sau khi xap xep hang %d",k);
for (i=1;i<=n;i++)
{ for (j=1;j<=n;j++)
printf ("%3d",A[i][j]);
printf("\n");
}}
/*voi k mot so bat ky nhap tu ban
phim in ra so lan xuat
hien cua k trong ma tran*/

t=t+A[i][i];
printf ("trung binh cong cac phan tu tren
duong cheo chinh=%35.1f",(float)n);
}
/*tich hai ma tran*/
void tich(int A[10][10],int B[10][10],int n)
{
int C[10][10],i,j,k;
for (i=1;i<=n;i++)
for (j=1;j<=n;j++)
{
C[i][j]=0;
for (k=1;k<=n;k++)C[i][j]=A[i][j]*B[i][j];
printf ("tich hai ma tran la %f",C[i][j]);
}
}
/*in ra man hinh cac phan tu trong
vung duoc danh dau
cua ma tran A*/
void in( int A[10][10],int n)
{
int i,j;
for (i=1;i<=n;i++)
{ for (j=1;j<=n;j++)
printf ("%3d",A[i][j]);
printf ("\n");
}
}
/*so sanh cac phan tu am va phan
tu duong trong ma tran*/

{
clrscr();
int A[10][10],n;
nhap(A,&n);
hienthi(A,n);
hienthihangchan(A,n);
xapxephang(A,n);
getch();
}
ma trận vuông
#include<stdio.h>
#include<conio.h>
int a[15][15];
int i,j;
void main()
{clrscr();
for(j=0;j<=9;j++)
{a[0][j]=j;printf("%3d",a[0][j]);}
printf("\n");
i=1;
while(i<=9)
{for(j=0;j<=9;j++)
{a[i][j]=a[i-1][j]+10;
printf("%3d",a[i][j]);
}
printf("\n");
i++;
}
getch();
}