Data_Structures Crib Sheet 1

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Rensselaer Polytechnic Institute CSCI 1200 // Initialize std::vector<type> vec; //Makes vec. of 10 doubles set to 3.1 std::vector<double> scores(10, 3.1); //Makes vec. b exact copy of scores. std::vector<double> b(scores); vec.empty() //Returns if vec is empty vec.size() //Returns size of vec vec.clear() ...[Show More]

Rensselaer Polytechnic Institute
CSCI 1200
// Initialize

std::vector<type> vec;

//Makes vec. of 10 doubles set to 3.1

std::vector<double> scores(10, 3.1);

//Makes vec. b exact copy of scores.

std::vector<double> b(scores);

vec.empty() //Returns if vec is empty

vec.size() //Returns size of vec

vec.clear() //NR clears values of vec

vec.insert(pos,val) //NR inserts value

vec.push_back(val) //NR adds val to

end of vector

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#include <algorithm>

std::sort(vec.begin(), vec.end(), opt);

//NR default is alphabetically

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#include <string>

// Initialize

std::string str;

std::string str = “hello”;

//Makes string of five ‘a’s “aaaaa”

std::string str(5,’a’)

str = “Susan”; // str[1] Equals ‘u’

//Makes temp. string that’s not

//assoc. with variable name.

std::string(num, ‘char’)

str.length() //Returns length of str

str.substrin(strt,end) //Returns

substr from strt to end inclusive

str.find(str1,pos) //Returns first pos

str1 was found in str.

str.rfind(str1) //Find, just last

occurrence

if (str.find(str1) != std::string::npos)

// It was found

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strings have double “quotes”

characters have single ‘quotes’

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#include <iostream>

std::cin >> std::cout << std::endl

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#include <fstream>

//Initialize in stream

std::ifstream in_stream(argv[1]);

//Initialize out stream

std::ofstream out_stream(argv[2]);

std::string word;

in_stream >> word;

word = word + “fart”;

out_stream << word;

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#include <cstdlib>

atoi(“str”) //Returns converted string

to integer

atof(“str”) //Returns converted string

to double

#include <iomanip>

std::setprecision(num) //Sets how

many numbers are displayed.

std::setprecision(4) << pi;  3.141

std::setw(num) //Sets width of

output line of next variable

std::setfill(‘char’) //Sets the fill

character to fill rest of space on line

std::right // Right justifies next var.

std::left // Left justifies next var.

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NO Inclusion

std::fixed //Prints number same as

what was produced. So 0.0000 not 0

std::scientific //Prints in sci. notation

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#include <cmath>

std::pow(n1,n2) //Returns power

std::sqrt(n1) //Returns sqrt of n1

std::ceil(num) //Returns num

rounded up to highest whole num

std::floor(num) //Returns num

rounded down to lowest whole num

std::abs(n1) //Returns abs val of n1

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int do_something(int& a, int& b)

/* Passing by reference (&) gives

address of original instead of copying

entire value into function.

If you make a change to “a” in

function, the original value will also

be changed.

Passing item by “const &” means

the item is not copied, but any

changes to it will not affect original

*/

---------------------------------------------

---------------------------------------------

int Date::getDay() const;

/* A const function merely means

that the function will not change any

of the values being passed into it.

Has const values usually or no

parameters at all. Cannot be used if

values are changing.

*/

------------------------------------------------

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const std::string& first_name() const;

/* This function is promising not to

change any values that it is using.

Also, it is saying that the

returned string will be passed by

reference to the user, not a copy of it.

But it’s saying that the user must not

change it either, since by reference

means they have the ability to if the

“const” is not there.

*/

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int main(int argc, char* argv[ ]){

//argc = num of arguments

//argv = value of each argument

return 0;

}

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static int counter; //Keeps val out of

scope, but only accessed in scope

#ifndef _ _student_h_

#define _ _student_h_

code{

// Put For All Header Files

}

#endif

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operator< (const Date& d1, “”)

// Makes less than operator

Pointers And Dynamic Memory:

new //word to create space on heap

delete //cleans up space on heap