Issue with code P: PP Drill 4 - c++

Question

I've been doing a drill from a book entitled Programming: Principles and Practice Using C++ by Bjarne Stroustrup, and this drill (Chapter 4) primarily deals with vectors. When I run the program, it doesn't give me any output at all. There are no compilation errors though. Here's the code:
#include "std_lib_facilities.h"
int main()
{
vector<double> value;
vector<string> units;
double max_val=-100000, min_val=100000;
double temp, sum=0;
int no_of_inputs=0;
string unit;
int i=0;
cout << "\nEnter the first value: " << endl;
// inputs values and units and assign them in vector value and vector unit respectively.
while (cin >> temp >> unit){
++no_of_inputs;
cout << "Enter the next value: " << endl;
value.push_back(temp);
units.push_back(unit);
}
// converts cm, in and ft to m;
for (i==0; i<units.size(); ++i){
if (units[i]== "cm" || units[i]== " cm"){
value[i] = value[i]/100.0;
}else if (units[i]== "in" || units[i]== " in"){
value[i] = value[i]/2.5/100.0;
}else if (units[i]== "ft" || units[i]== " ft"){
value[i] = value[i]*12/2.5/100.0;
}else if (units[i]=="m" || units[i]== " m"){
}else cout << "\n\n" << value[i] << " " << units[i] << " is an incorrect input value.";
return 0;
}
// Identifies the max_value and the min_value. Also adds all values.
for (i==0; i<value.size(); ++i){
if (value[i]>max_val){
max_val=value[i];
}
if (value[i]<min_val){
min_val=value[i];
}
sum += value[i];
}
// outputs all values entered (converted to meters)
cout << "\nValues Entered:"<< endl;
sort(value);
for (i==0; i<value.size(); ++i){
cout << value[i] << " meters" << endl;
}
cout << "Total: " << sum << " meters" << endl;
cout << "Smallest value: " << min_val << endl;
cout << "Largest value: " << max_val << endl;
cout << "Total values entered: " << no_of_inputs << endl;
return 0;
}
Can anyone tell me why it is not working?

Answer 1

you have 2 mistakes. The main reason for terminating your program is here
else cout << "\n\n" << value[i] << " " << units[i] << " is an incorrect input value."; return 0;
you putting return in the first for loop. I guess you may think return is belong to else but because you don't use scope determiner {} only 1 instruction (cout) is belong to else and return is executed every time.
your second mistake is use i==0 instead of i=0 in for loops.
your correct code is this :
vector<double> value;
vector<string> units;
double max_val = -100000, min_val = 100000;
double temp, sum = 0;
int no_of_inputs = 0;
string unit;
int i = 0;
cout << "\nEnter the first value: " << endl;
//inputs values and units and assign them in vector value and vector unit respectively.
while (cin >> temp >> unit){
++no_of_inputs;
cout << "Enter the next value: " << endl;
value.push_back(temp);
units.push_back(unit);
}
//converts cm, in and ft to m;
for (i = 0; i<units.size(); ++i){
if (units[i] == "cm" || units[i] == " cm"){
value[i] = value[i] / 100.0;
}
else if (units[i] == "in" || units[i] == " in"){
value[i] = value[i] / 2.5 / 100.0;
}
else if (units[i] == "ft" || units[i] == " ft"){
value[i] = value[i] * 12 / 2.5 / 100.0;
}
else if (units[i] == "m" || units[i] == " m")
{
}
else
{
cout << "\n\n" << value[i] << " " << units[i] << " is an incorrect input value.";
return 0;
}
}
//Identifies the max_value and the min_value. Also adds all values.
for (i = 0; i<value.size(); ++i){
if (value[i]>max_val){
max_val = value[i];
}
if (value[i]<min_val){
min_val = value[i];
}
sum += value[i];
}
//outputs all values entered (converted to meters)
cout << "\nValues Entered:" << endl;
//sort(value);
for (i = 0; i<value.size(); ++i){
cout << value[i] << " meters" << endl;
}
cout << "Total: " << sum << " meters" << endl;
cout << "Smallest value: " << min_val << endl;
cout << "Largest value: " << max_val << endl;
cout << "Total values entered: " << no_of_inputs << endl;
return 0;