Giải tiếp các bài trong giáo trình !!

(bai 14 tr980)dung con tro nhap day ky tu thay di ky tu 'a' thanh 'b' roi xuat

Mã:

//(bai 14 tr980)dung con tro nhap day ky tu thay di ky tu 'a' thanh 'b' roi xuat
#include<iostream.h>
#include<string>
using namespace std;
int main()

{
	int i,n;
	char *p;
	p=new char[100];
	cout<<"Moi nhap chuoi ky tu (phai co chu a nhe ) ";
	cin.getline(p,100);
	n=strlen(p);
	for(i=0;i<n;i++)
	{if(p[i]=='a')
			p[i]='b';
	}
	cout<<"chuoi da duoc thay doi :"<<endl;
	cout<<p<<endl;
	return 0;
}

cho sau ky tu(dang con tro) .hay in nguoc sau ra mang hinh

Mã:

//cho sau ky tu(dang con tro) .hay in nguoc sau ra mang hinh
#include<iostream.h>
#include<string>
using namespace std;
int main()
{
	char *p;
	int i,n;
	p=new char[100];
	cout<<"Moi nhap chuoi :";
	cin.getline(p,100);
	n=strlen(p);
	cout<<" Chuoi in nguoc la "<<endl;
	for(i=n-1;i>=0;i--)
		cout<<p[i];
	cout<<endl;
	return 0;
}

(Bai 19 tr 99)dung con tro copy tu s sang t doan bat dau tu vi tri m voi do dai n

Mã:

//dung con tro copy tu s  sang t doan bat dau tu vi tri m voi do dai n
#include<iostream.h>
#include<string>
using namespace std;
int main()
{
	int m,n;
	char *s,*t;
	s=new char[100];
	t=new char[100];
	cout<<"Moi nhap sau ky tu s";
	cin.getline(s,100);
	cout<<"moi nhap vi tri m :"<<endl;
	cin>>m;
	cout<<"moi nhap vi tri n :"<<endl;
	cin>>n;
	cout<<strncat(t,s+m,n);
	return 0;
}

(bai 21 tr99)nhap sau thong ke cac chu so '0'....'9' co trong sau.

Mã:

//(bai 21 tr99)nhap sau thong ke cac chu so '0'....'9' co trong sau.
#include<iostream.h>
#include<string>
using namespace std;
int main()
{
	int i,n,a[10];
	char str[100];
	cout<<"Moi nhap sau :"<<endl;
	cin.getline(str,100);
	n=strlen(str);
	for(i=0;i<=9;i++)
		a[i]=0;
		for(i=0;i<n;i++)
			if(str[i]>='0'&&str[i]<='9')
				a[str[i]-'0']++;
			for(i=0;i<=9;i++)
				cout<<"co "<<a[i]<<"so "<<i<<endl;
			return 0;
}