Download cmsc245, study guide for your final test

cmsc245, study guide for your final test
DO and DO NOT
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do study all the old tests
do study all the programming projects
do ask TAs if you have doubts
do read the book
do ask for clarifications during the test
do not panic
do not be later
do not mess up the examine paper
Book sections to read:
 2.1, 2.2 basic types, variable, C++ program structure.
 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, expressions
o numerical Expression, +,-,*,/,%,
o Logical (Boolean) expression: ==, >, <, >=, <=, !, &, |,
o charact exp
o all mixed up expression.
 4.2, 4.3, 4.4: functions, if, local variables, and for
statements
 5.4: string and related operations.
o [], +, <<, ==, <, >
o size(), empty(), substr(), replace(), find()
 6.1, 6.2: if statements
o nested if statements
o = and ==
 9.2: file IO
o ifstream, ofstream
o open(), getline(), eof(), close()
 10.2: array
o using for loop to process array data
o index
o swap, insert, delete
some code reading exercise
string and array
#include <iostream>
#include <fstream>
#include<string>
using namespace std;
void testfun()
{
cout<<"hello"<<endl;
cout<<"world"<<endl;
}
void testfunc2()
{
int arrayx[5];
int * ptr;
ptr=0;
*(ptr)=1;
}
int main()
{
char carray[100]="abcdefg";
string s1,
s2="row, row, row you boat",
s3="row",
s4="boat";
cout << s2[3];
cout<< s1.size()+s4.size();
cout<<s1.length();
cout<< (s3 < s4);
s1= s3 + s4;
cout<<s1;
cout<< "xxx"+s1+s2+s4+"end"<<endl;
cout<<s2.substr(1,3)<<endl;
cout << s2.find("ow",0)<<endl;
cout << s2.find("ow", 10)<<endl;
s1=s2;
cout<<s1<<endl;
int ind;
ind=s1.find("b",0);
s1[ind]='g';
for (int i=0;i<=10;i+=5)
{
s1[i]='m';
}
cout<< s1 << endl;
}
file IO
include <iostream>
#include <fstream>
#include<string>
using namespace std;
int main()
{
int intarray[1000];
int newValue;
int totalnum=0;
ifstream inStream;
//inStream.open(filename); //call the open function with the
provided filename path
inStream.open("C:\\CMSC245\\p5\\fileio\\fileio\\p6data.txt");
if (inStream==0){
cout<<"\nfile not exist, return\n";
//return 0;
}
int i;
string empname;
int length;
int firstspace;
int secondspace;
string oneline;
string firstname[100];
string lastname[100];
string agestr;
int age[100];
//getline(inStream, empname);
cout<<endl;
for(;;)
{
getline(inStream,oneline);
if (inStream.eof()) break;
length=oneline.size();
cout <<oneline;
firstspace=oneline.find(" ",0);
firstname[totalnum]=oneline.substr(0,firstspace);
secondspace=oneline.find(" ",firstspace+1);
lastname[totalnum]=oneline.substr(firstspace+1,secondspacefirstspace);
agestr= oneline.substr(secondspace+1,length-secondspace);
age[totalnum]=atoi(agestr.c_str());
//two steps con:
string->c-str (char array)->int
cout<<"First Name:"<<firstname[totalnum]<<"...."<<"Last
Name:";
cout<<lastname[totalnum]<<"....Age:"<<age[totalnum]<<endl;
//intarray[totalnum]=newValue;
totalnum++;
}
for (i=0;i<totalnum;i++) cout<< intarray[i] <<" ";
cout<<endl;
inStream.close();
ofstream outStream;
//inStream.open(filename); //call the open function with the
provided filename path
outStream.open("C:\\CMSC245\\p5\\fileio\\fileio\\p6dataout.txt");
if (outStream==0){
cout<<"\nfile not exist, return\n";
//return 0;
}
for(i=0;i<totalnum;i++)
outStream<<firstname[i]<<" "<<age[i]<<" "<<lastname[i]<<endl;
outStream.close();
}
more on array
double xValue[5];
for ( int i =0; i<=4;i++) xValue[i]= double (i)/2.0;
i
xValue
1
0
{0.00,,,,}
2
1
{0.00,
0.5,,,}
3
2
{0.00,
0.5,
1.0,,,}
4
5
3
4
{0.00,0.5,1.0,1.5,,} {0.00,0.5,1.0,1.5,2.0}
20 for (int i=0; i<5; i++)
if (i%2 ==0) number [i] = 2*i;
else number [i] = 2*i+1;
i
i%2
i%2 ==0
number[]
1
0
0
True 1
{0,,,,}
2
1
1
False 0
{0,3,,,}
3
2
0
True 1
{0,3,4,,}
4
3
1
False 0
{0,3,4,7
5
4
0
True 1
{0,3,4,7,8}
Do the following exercises! make sure you get it.
int number[5]={1};
for (int i =1;i<5;i++)
number[i]=2*number[i-1];
number[4]=3;
for (int i=3;i>=0;i--) number[i]=2*number[i+1];
int number[8]={1,9,8,4,6,2,3,5}
int tmp;
for (int i=0;i<5;i++) {
if (number[i] > number[8-i-1])
{
tmp=number[i];
number[8-i-1]=tmp;
number[i]= number[8-i-1]
}
}
prime number
*
Program to find prime numbers till 'n' !!
*/
#include <iostream>
#include <math.h>
using namespace std;
void list(int n);
bool prime_num(int num);
void main()
{
int num;
cout << "Enter a number :";
cin >> num;
list(num);
}
void list(int n)
{
bool isPrime;
cout << "The prime numbers less than " << n << " are :";
cout << "2";
for (int i=3; i<n; i++)
{
isPrime = prime_num(i);
if(isPrime)
{
cout << " " << i;
}
}
cout << "\n";
}
bool prime_num(int num)
{
bool a = true;
for (int j=2; j<=sqrt((double)num); j++)
{
if (((int)num%j)== 0)
{
a = false;
between 2 - square root of number
}
}
return a;
}
if statement and expressions
void main()
{
int y=0, x = 5,z = 2,m=0;
for (x=5; x >1;x=x-1) {
m=x+m;
if (x>y)
if(x>z) m=x;
else m=z;
else if (y>z) m=y
else m=z;
y=y+2;
z=z+1;
cout<<“x is”<<x;
cout<< "m is”<<m ;
}
cout<<"m is: ” +m ;
}
}