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View Full Version : Error: cannot convert `std::string' to `int' in initialization



hans_cellc
12-22-2011, 01:07 PM
Please assist got the following code that I need to do calculations extracted from a substr.


// ID_Verification
#include <iostream>
#include <string>
using namespace std;

int main()
{
// Initialise strings - originaly id should be interger but made a string to split into substr
string id, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen;
// Initialise char for the yes or no answer to come
char correct;

cout << "***** South African ID Verification *****" << endl << endl;
cout << "Enter ID number: ";
// Enter the id number
cin >> id;

// Initialise an length interger based on the length of the id string
int length = id.size();

// a While loop to ensure that the id number consists of 13 digits
while(length != 13) {
cout << "This is too short or too long for a SA ID number!" << endl;
cout << "Enter ID number: ";
cin >> id;
length = id.size();
}

// Allocate specific position values of the id number to be used in later calculations
one = id.substr(0,1);
two = id.substr(1,1);
three = id.substr(2,1);
four = id.substr(3,1);
five = id.substr(4,1);
six = id.substr(5,1);
seven = id.substr(6,1);
eight = id.substr(7,1);
nine = id.substr(8,1);
ten = id.substr(9,1);
eleven = id.substr(10,1);
twelve = id.substr(11,1);
thirteen = id.substr(12,1);

// Print the entered id number
cout << endl << "ID number: " << one << two << three << four << five << six
<< seven << eight << nine << ten << eleven << twelve << thirteen << endl;

// Confirm correct entry
cout << "Entered correctly? (Y / N) ";
cin >> correct;

// while loop to ensure char Y y N n only to be selected
while(correct != 'Y' && correct != 'y' && correct != 'N' && correct != 'n') {
cout << "Entered correctly? (Y / N) ";
cin >> correct;
}

// while loop to restart if incorrect entry
while(correct == 'N' || correct == 'n') {
cout << "Enter ID number: ";
cin >> id;

length = id.size();

while(length != 13) {
cout << "This is too short or too long for a SA ID number!" << endl;
cout << "Enter ID number: ";
cin >> id;
length = id.size();
}
one = id.substr(0,1);
two = id.substr(1,1);
three = id.substr(2,1);
four = id.substr(3,1);
five = id.substr(4,1);
six = id.substr(5,1);
seven = id.substr(6,1);
eight = id.substr(7,1);
nine = id.substr(8,1);
ten = id.substr(9,1);
eleven = id.substr(10,1);
twelve = id.substr(11,1);
thirteen = id.substr(12,1);

cout << endl << "ID number: " << one << two << three << four << five << six
<< seven << eight << nine << ten << eleven << twelve << thirteen << endl;
cout << "Entered correctly? (Y / N) ";
cin >> correct;
}

// The start of the calculations - However need string converted to interger
int first = one + three + five + seven + nine + eleven; // Error: cannot convert `std::string' to `int' in initialization

// Test calculations thusfar
cout << first << endl;

return 0;
}

Apothem
12-22-2011, 08:06 PM
Yes. Simply put, yes.

You are concatenating (NOT summing) strings, then assigning this string to an integer.
atoi(myString.c_str()) may be what you want to do for each string.

hans_cellc
12-22-2011, 08:41 PM
Thanks a mil it worked perfectly as per the code below.
Now however I need to convert an interger to a string.
I can then use the same method to add the values but first need to convert it.
Any ideas?


// ID_Verification
#include <iostream>
#include <string>
using namespace std;

int main()
{
// Initialise strings - originaly id should be interger but made a string to split into substr
string id, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen;
// Initialise char for the yes or no answer to come
char correct;

cout << "***** South African ID Verification *****" << endl << endl;
cout << "Enter ID number: ";
// Enter the id number
cin >> id;

// Initialise an length interger based on the length of the id string
int length = id.size();

// a While loop to ensure that the id number consists of 13 digits
while(length != 13) {
cout << "This is too short or too long for a SA ID number!" << endl;
cout << "Enter ID number: ";
cin >> id;
length = id.size();
}

// Allocate specific position values of the id number to be used in later calculations
one = id.substr(0,1);
two = id.substr(1,1);
three = id.substr(2,1);
four = id.substr(3,1);
five = id.substr(4,1);
six = id.substr(5,1);
seven = id.substr(6,1);
eight = id.substr(7,1);
nine = id.substr(8,1);
ten = id.substr(9,1);
eleven = id.substr(10,1);
twelve = id.substr(11,1);
thirteen = id.substr(12,1);

// Print the entered id number
cout << endl << "ID number: " << one << two << three << four << five << six
<< seven << eight << nine << ten << eleven << twelve << thirteen << endl;

// Confirm correct entry
cout << "Entered correctly? (Y / N) ";
cin >> correct;

// while loop to ensure char Y y N n only to be selected
while(correct != 'Y' && correct != 'y' && correct != 'N' && correct != 'n') {
cout << "Entered correctly? (Y / N) ";
cin >> correct;
}

// while loop to restart if incorrect entry
while(correct == 'N' || correct == 'n') {
cout << "Enter ID number: ";
cin >> id;

length = id.size();

while(length != 13) {
cout << "This is too short or too long for a SA ID number!" << endl;
cout << "Enter ID number: ";
cin >> id;
length = id.size();
}
one = id.substr(0,1);
two = id.substr(1,1);
three = id.substr(2,1);
four = id.substr(3,1);
five = id.substr(4,1);
six = id.substr(5,1);
seven = id.substr(6,1);
eight = id.substr(7,1);
nine = id.substr(8,1);
ten = id.substr(9,1);
eleven = id.substr(10,1);
twelve = id.substr(11,1);
thirteen = id.substr(12,1);

cout << endl << "ID number: " << one << two << three << four << five << six
<< seven << eight << nine << ten << eleven << twelve << thirteen << endl;
cout << "Entered correctly? (Y / N) ";
cin >> correct;
}

// The start of the calculations - However need string converted to interger
// int first = one + three + five + seven + nine + eleven; // Error: cannot convert `std::string' to `int' in initialization
// Convert strings to intergers
int first = atoi(one.c_str());
int second = atoi(two.c_str());
int third = atoi(three.c_str());
int fourth = atoi(four.c_str());
int fith = atoi(five.c_str());
int sixth = atoi(six.c_str());
int seventh = atoi(seven.c_str());
int eighth = atoi(eight.c_str());
int ninth = atoi(nine.c_str());
int tenth = atoi(ten.c_str());
int eleventh = atoi(eleven.c_str());
int twelth = atoi(twelve.c_str());
int thirteenth = atoi(thirteen.c_str());

// First Calculation - Add all the digits of the ID number in the odd positions
// (except for the last number, which is the control digit):
int calc1 = first + third + fith + seventh + ninth + eleventh;

// Second Calculation - Take all the even digits as one number and multiply that by 2
string calc2a = two + four + six + eight + ten + twelve;
int calc2 = atoi(calc2a.c_str());
calc2 = calc2 * 2;

// Third Calculation - Add the digits of this number together (in calc2)
// Convert answer in calc2 back to a string and then add them together
string calc3a = calc2;

// Test calculations thusfar
cout << calc1 << endl;
cout << calc2 << endl;
cout << calc3a << endl;

return 0;
}

Apothem
12-22-2011, 08:50 PM
string convertInt(int number)
{
stringstream ss; //create a stringstream
ss << number; //add number to the stream
return ss.str(); //return a string with the contents of the stream
}
from: http://www.cplusplus.com/forum/beginner/7777/

hans_cellc
12-24-2011, 02:14 PM
:)thanks for help on this small project. First of many.:)


// ID_Verification
// 24/12/11 10:56
// Author: SJ Fouche
// Email: hans_cellc@yahoo.com

#include <iostream>
#include <string>
using namespace std;


int main()
{
// Initialise strings - originaly id should be interger but made a string to split into substr
string id, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen;
// Initialise char for the yes or no answer to come
char correct;

cout << "***** South African ID Verification *****" << endl << endl;
cout << "Enter ID number: ";
// Enter the id number
cin >> id;

// Initialise an length interger based on the length of the id string
int length = id.size();

// a While loop to ensure that the id number consists of 13 digits
while(length != 13) {
cout << "This is too short or too long for a SA ID number!" << endl;
cout << "Enter ID number: ";
cin >> id;
length = id.size();
}

// Allocate specific position values of the id number to be used in later calculations
one = id.substr(0,1);
two = id.substr(1,1);
three = id.substr(2,1);
four = id.substr(3,1);
five = id.substr(4,1);
six = id.substr(5,1);
seven = id.substr(6,1);
eight = id.substr(7,1);
nine = id.substr(8,1);
ten = id.substr(9,1);
eleven = id.substr(10,1);
twelve = id.substr(11,1);
thirteen = id.substr(12,1);

// Print the entered id number
cout << endl << "ID number: " << one << two << three << four << five << six
<< seven << eight << nine << ten << eleven << twelve << thirteen << endl;

// Confirm correct entry
cout << "Entered correctly? (Y / N) ";
cin >> correct;

// while loop to ensure char Y y N n only to be selected
while(correct != 'Y' && correct != 'y' && correct != 'N' && correct != 'n') {
cout << "Entered correctly? (Y / N) ";
cin >> correct;
}

// while loop to restart if incorrect entry
while(correct == 'N' || correct == 'n') {
cout << "Enter ID number: ";
cin >> id;

length = id.size();

while(length != 13) {
cout << "This is too short or too long for a SA ID number!" << endl;
cout << "Enter ID number: ";
cin >> id;
length = id.size();
}
one = id.substr(0,1);
two = id.substr(1,1);
three = id.substr(2,1);
four = id.substr(3,1);
five = id.substr(4,1);
six = id.substr(5,1);
seven = id.substr(6,1);
eight = id.substr(7,1);
nine = id.substr(8,1);
ten = id.substr(9,1);
eleven = id.substr(10,1);
twelve = id.substr(11,1);
thirteen = id.substr(12,1);

cout << endl << "ID number: " << one << two << three << four << five << six
<< seven << eight << nine << ten << eleven << twelve << thirteen << endl;
cout << "Entered correctly? (Y / N) ";
cin >> correct;
}

// The start of the calculations - However need string converted to interger
// int first = one + three + five + seven + nine + eleven; // Error: cannot convert `std::string' to `int' in initialization
// Convert strings to intergers
int first = atoi(one.c_str());
int second = atoi(two.c_str());
int third = atoi(three.c_str());
int fourth = atoi(four.c_str());
int fith = atoi(five.c_str());
int sixth = atoi(six.c_str());
int seventh = atoi(seven.c_str());
int eighth = atoi(eight.c_str());
int ninth = atoi(nine.c_str());
int tenth = atoi(ten.c_str());
int eleventh = atoi(eleven.c_str());
int twelth = atoi(twelve.c_str());
int thirteenth = atoi(thirteen.c_str());

// First Calculation - Add all the digits of the ID number in the odd positions
// (except for the last number, which is the control digit):
int calc1 = first + third + fith + seventh + ninth + eleventh;

// Second Calculation - Take all the even digits as one number and multiply that by 2
string calc2a = two + four + six + eight + ten + twelve;
int calc2 = atoi(calc2a.c_str());
calc2 = calc2 * 2;

// Third Calculation - Add the digits of this number together (in calc2)
// Convert answer in calc2 back to a string and then add them together
char b[50];
string calc3a;
sprintf(b,"%d",calc2);// C-style string formed without null
calc3a += b;
string numberz[20];
int numbers[20];
int calc3 = 0;
int stringLength = calc3a.size();

for(int i = 0; i < stringLength; i++) {
numberz[i] = calc3a.substr(i,1);
numbers[i] = atoi(numberz[i].c_str());
calc3 += numbers[i];
}

// Fourth Calculation - Add the answer of calc3 to the answer of calc1
int calc4 = calc3 + calc1;

// Fith calculation - Subtract the second character from calc4 from 10,
// this number should now equal the control character
char c[50];
string calc5a;
sprintf(c,"%d",calc4);// C-style string formed without null
calc5a += c;
string secondNum = calc5a.substr(1, 1);
int secondNumber = atoi(secondNum.c_str());
int answer = 10 - secondNumber;

// Test calculations thusfar
//cout << calc1 << endl;
//cout << calc2 << endl;
//cout << calc3a << endl;
//cout << calc3 << endl;
//cout << calc4 << endl;
//cout << calc5a << endl;
//cout << secondNum << endl;
//cout << secondNumber << endl;
//cout << answer << endl;
//cout << thirteenth << endl;

// Check answer to equal control character (thirteenth)
if(answer == thirteenth || answer == 10){
cout << endl << "*****************************************" << endl;
cout << "***** Valid South African ID number *****" << endl;
cout << "*****************************************" << endl;
}
else {
cout << endl << "*****************************************" << endl;
cout << "***** INVALID South African ID number *****" << endl;
cout << "*****************************************" << endl;
}

// Wait for enter to end execution
cin.get();
return 0;
}



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