ch4_drill

Drill 01

//Write a program that consists of a while-loop that (each time around// the loop) reads in two ints and then prints them. Exit the program when//a terminating '|' is entered.#include "std_lib_facilities.h"int main(){int val1, val2;while(cin >> val1 >> val2)cout << val1 << '/t' << val2 << '/n';}

 

Drill 02

//Change the program to write out the smaller value is: followed //by the smaller of the numbers and the larger value is: followed //by the larger value.#include "std_lib_facilities.h"int main(){int val1, val2;while(cin >> val1 >> val2)if( val1 < val2)cout << "the smaller value is: " << val1 << '/n'<< "the larger value is: " << val2 << '/n';elsecout << "the smaller value is: " << val2 << '/n'<< "the larger value is: " << val1 << '/n';cout << '/n';}

 

Drill 03

//Augment the program so that is writes the line the numbers are//equal(only) if they are equal#include "std_lib_facilities.h"int main(){int val1, val2;while(cin >> val1 >> val2){if( val1 < val2)cout << "the smaller value is: " << val1 << '/n'<< "the larger value is: " << val2 << '/n';else if(val1 > val2)cout << "the smaller value is: " << val2 << '/n'<< "the larger value is: " << val1 << '/n';elsecout << "the numbers are equal" << '/n';cout << '/n';}}

 

Drill 04

//Change the program so that it uses doubles instead of ints.#include "std_lib_facilities.h"int main(){double val1, val2;while(cin >> val1 >> val2){if( val1 < val2)cout << "the smaller value is: " << val1 << '/n'<< "the larger value is: " << val2 << '/n';else if(val1 > val2)cout << "the smaller value is: " << val2 << '/n'<< "the larger value is: " << val1 << '/n';elsecout << "the numbers are equal" << '/n';cout << '/n';}}

 

Drill 05

//Change the program so that it writes out the numbers are almost equal//after writing out which is the larger and the smaller if the two numbers //differ by less thann 1.0/100.#include "std_lib_facilities.h"int main(){double val1, val2, result;while(cin >> val1 >> val2){result = val1 - val2;if( result < 1.0/100 && result >0)cout << "the numbers are almost equal"<< '/n' << "the smaller value is: " << val2 << '/n' << "the larger value is: " << val1 << '/n';else if(result < 0 && result > -1.0/100)cout << "the numbers are almost equal"<< '/n' << "the smaller value is: " << val1 << '/n' << "the larger value is: " << val2 << '/n';else if(result > 1.0/100)cout << "the smaller value is: " << val2 << '/n' << "the larger value is: " << val1 << '/n';elsecout << "the smaller value is: " << val1 << '/n' << "the larger value is: " << val2 << '/n';cout << '/n';}}

 

Drill 06

//Now change the body of the loop so that is reads just one double each//time around. Define two variables to keep track of which is the smallest//and which is the largest value you have seen so far. Each time through//the loop write out the value entered. If it's the smallest so far, write the//smallest so far after the number. If it is the largest so far, write the largest //so far after the number#include "std_lib_facilities.h"int main(){double length, smallest, largest;//初始化最大最小值cin >> length; smallest = length;cin >> length;if(smallest > length) //如果名不符实，交换变量中的值{largest = smallest;smallest = length;}elselargest = length;//判断最值while(cin >> length) {cout << "the smallest so far: " << smallest << '/n'<< "the largest so far: " << largest << '/n';if(length < smallest)smallest = length;else if(length >largest)largest = length;cout << '/n';}}

 

Drill 07

//Add a unit to each double entered; that is, enter values such as 10cm,//2.5in, 5ft, or 3.33cm. Accept the four units: cm, m, in, ft. Assume conversion//factors 1m == 100cm, 1in == 2.54cm, 1ft == 12in. Read the unit indicator //into a string#include "std_lib_facilities.h"int main(){double length = 1.0;string unit = "abc";cout << "Please enter a length followed by a unit(cm, m, in or ft): " << '/n';while(cin >> length >> unit){if(unit == "cm")cout << length << "cm == " << length/100 << "m/n";else if(unit == "m")cout << length << "m == " << length*100 << "cm/n";else if(unit == "in")cout << length << "in == " << length*2.54 << "cm/n";else if(unit == "ft")cout << length << "ft == " << length*12 << "in/n";elsecout << "Sorry, I don't know a unit called '" << unit << "'./n";cout << '/n';}}

 

Drill 09

//Keep track of the sum of values entered (as well as the smallest and the //largest) and the number of values entered. When you see the final '|'//print the smallest, the largest, the number of values, and the sum of values.//Note that to keep the sum, you have to decide on a unit to use for//hat sum; use meters.#include "std_lib_facilities.h"int main(){double sum = 0, length = 1.0, smallest, largest;string unit = "abc";double unify_length(double, string);cout << "Please enter a length followed by a unit(cm, m, in or ft): " << '/n';cin >> length >> unit;smallest = unify_length(length, unit);cin >> length >> unit;if(smallest > unify_length(length, unit)) {largest = smallest;smallest = unify_length(length, unit);}elselargest = unify_length(length, unit);sum = smallest + largest;for(int counter = 2; cin >> length >> unit; ++counter){cout << "the smallest so far: " << smallest << '/n'<< "the largest so far: " << largest << '/n'<< "the sum so far: " << sum << '/n'<< "the number so far: " << counter << '/n';if(unify_length(length, unit) < smallest)smallest = unify_length(length, unit);else if(unify_length(length, unit) >largest)largest = unify_length(length, unit);sum += unify_length(length, unit);cout << '/n';}}//统一单位double unify_length(double sub_length, string sub_unit){double u_length = 1.0;if(sub_unit == "cm")u_length = sub_length/100;else if(sub_unit == "m")u_length = sub_length;else if(sub_unit == "in")u_length = sub_length*2.54/100;else if(sub_unit == "ft")u_length = 12*sub_length*2.54/100;elsecout << "Sorry, I don't know a unit called '" << sub_unit << "'./n";return u_length;}

 

Drill 10

//Keep all the values entered (convered into meters) in a vector. At the//end, write out those values.#include "std_lib_facilities.h"int main(){double sum = 0, length = 1.0, smallest, largest;string unit = "abc";vector<double>unilengths;double unify_length(double, string);cout << "Please enter a length followed by a unit(cm, m, in or ft): " << '/n';cin >> length >> unit;smallest = unify_length(length, unit);unilengths.push_back(smallest);cin >> length >> unit;if(smallest > unify_length(length, unit)) //如果输入值比最小变量中的值小{largest = smallest; //将最小变量中的值给最大变量smallest = unify_length(length, unit); //输入值放入最小变量中unilengths.push_back(smallest);}else{largest = unify_length(length, unit); //否则输入值给最大变量unilengths.push_back(largest);}sum = smallest + largest;for(int counter = 2; cin >> length >> unit; ++counter){cout << "the smallest so far: " << smallest << '/n'<< "the largest so far: " << largest << '/n'<< "the sum so far: " << sum << '/n'<< "the number so far: " << counter << '/n';if(unify_length(length, unit) < smallest){smallest = unify_length(length, unit);unilengths.push_back(smallest);}else if(unify_length(length, unit) >largest){largest = unify_length(length, unit);unilengths.push_back(largest);}sum += unify_length(length, unit);cout << '/n';}for(unsigned int mark=0; mark < unilengths.size(); ++mark)cout << unilengths[mark] << '/n';}//统一单位double unify_length(double sub_length, string sub_unit){double u_length = 1.0;if(sub_unit == "cm")u_length = sub_length/100;else if(sub_unit == "m")u_length = sub_length;else if(sub_unit == "in")u_length = sub_length*2.54/100;else if(sub_unit == "ft")u_length = 12*sub_length*2.54/100;elsecout << "Sorry, I don't know a unit called '" << sub_unit << "'./n";return u_length;}

 

Drill 11

//Before writing out the values from the vector, sort them (that'll make//them come out in increasing order).#include "std_lib_facilities.h"int main(){double sum = 0, length = 1.0, smallest, largest;string unit = "abc";vector<double>unilengths;double unify_length(double, string);cout << "Please enter a length followed by a unit(cm, m, in or ft): " << '/n';cin >> length >> unit;smallest = unify_length(length, unit);unilengths.push_back(smallest);cin >> length >> unit;if(smallest > unify_length(length, unit)) //如果输入值比最小变量中的值小{largest = smallest; //将最小变量中的值给最大变量smallest = unify_length(length, unit); //输入值放入最小变量中unilengths.push_back(smallest);}else{largest = unify_length(length, unit); //否则输入值给最大变量unilengths.push_back(largest);}sum = smallest + largest;for(int counter = 2; cin >> length >> unit; ++counter){cout << "the smallest so far: " << smallest << '/n'<< "the largest so far: " << largest << '/n'<< "the sum so far: " << sum << '/n'<< "the number so far: " << counter << '/n';if(unify_length(length, unit) < smallest){smallest = unify_length(length, unit);unilengths.push_back(smallest);}else if(unify_length(length, unit) >largest){largest = unify_length(length, unit);unilengths.push_back(largest);}sum += unify_length(length, unit);cout << '/n';}sort(unilengths.begin(), unilengths.end());for(unsigned int mark=0; mark < unilengths.size(); ++mark)cout << unilengths[mark] << '/n';}//统一单位double unify_length(double sub_length, string sub_unit){double u_length = 1.0;if(sub_unit == "cm")u_length = sub_length/100;else if(sub_unit == "m")u_length = sub_length;else if(sub_unit == "in")u_length = sub_length*2.54/100;else if(sub_unit == "ft")u_length = 12*sub_length*2.54/100;elsecout << "Sorry, I don't know a unit called '" << sub_unit << "'./n";return u_length;}