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Expected primary expression before ';' token

OspreyR10A (4)
Hi Everyone,

I'm writing a calculator program and when I compile I get the following error code.

Expected primary expression before ';' token (which is line 57)

This is a work in progress and is not finished but I would like to run it to check my menu navigation. The program will run but it I cant select the menu option I would like. When I do select another option in the menu I get the correct submenu title, but it will continue with the first menu option regardless of the choice made.

To clarify the following is what I'm intending to happen:
1. The main menu will show up wit the 8 options using cout

2. Prompt user for a selection and have a cin to the int mainchoice variable.

3. The switch (mainchoice) then will cout the menu title chosen by the user (ie if the user presses 1, it will show up the first option in the menu).

4. After the switch (mainchoice), the if statement if (mainchoice = 1) will check if the input was 1 or not, if the input was 1, continue to sub routine for 4-20mA. If the input was not 1, move down to the if (mainchoice = 2) and if the input was two continue to sub routine for flow calculations.

Above is how the menu should work however when I select any option (1-8) I get the submenu title come up but then it runs the 4-20mA sub routine anyway.
I'm trying to use a nested if here, and I don't think I have done it right.

Any help on either of the above issues would be great.

Thank you in advance.

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#include <cstdlib>
#include <iostream>
#include <conio.h>
#include <iomanip>

using namespace std;

int main()
{

//Assigning variables
    int mainchoice = 0; //menu option
    //4-20mA Sub Routine
    string engunit; 
    float marange = 0; 
    float currentma = 0;
    float scaledval = 0; 
    int maorscaled = 0; 
    float ans1 =0; 
    float ans1a = 0; 
    float ans2 =0; 
    double ans2a = 0; //NOT WORKING AT PRESENT
    
    //Flow Sub Routine
    int engunita = 0; 
    int engunitb = 0; 
    float flowval1 = 0; 
    
    //Flow Tags
    float lpstolpm = 0; 
    float lpstolph = 0; 
    float lpstomcph = 0; 
    float lpstomcpd = 0;
    float lpstomld = 0; 
    
    float lpmtolps = 0; 
    float lpmtolph = 0; 
    float lpmtomcph = 0;
    float lpmtomcpd = 0;
    float lpmtomld = 0; 
    
    float lphtolps = 0; 
    float lphtolpm = 0; 
    float lphtomcph = 0; 
    float lphtomcpd = 0; 
    float lphtomld = 0; 
        
    
    cout << " Main Menu\n\n";
    cout << "\t\t1 - 4-20mA\n";
    cout << "\t\t2 - Flow\n";
    cout << "\t\t3 - \n";
    cout << "\t\t4 - \n";
    cout << "\t\t5 - \n";
    cout << "\t\t6 - \n";
    cout << "\t\t7 - \n";
    cout << "\t\t8 - \n";
    
    
    cout << "\n Please select which calculator: ";
    cin >> mainchoice;
    
    switch (mainchoice)
        {
        case 1: cout << "\n4-20mA\n\n\n";
            break;
        case 2: cout << "\nFlow.\n";
            break;
        case 3: cout << "\nTime.\n";
            break;
        case 4: cout << "\nOvercurrent i2t.\n";
            break;
        case 5: cout << "\nCT Wire Size.\n";
            break;
        case 6: cout << "\nWet Well Volume.\n";
            break;
        case 7: cout << "\nPercentage.\n";
            break;
        case 8: cout << "\nThree Phase.\n";
            break;
        default: cout << "\nInvalid Response.\n";
        }

 if(mainchoice = 1)
    { //Sub routine for 4-20mA
        cout << "Please enter an engneering unit: ";
        cin >> engunit;
        cout << "\nPlease enter the range of the instrument: ";
        cin >> marange;
        cout << "\nChoose to enter either a milliamp reading or scaled"
                << " value, make your choice.\n\n\t\t1. Milliamp reading.\n\t\t2. Scaled Value\n";
        cin >> maorscaled;
        switch (maorscaled)
            {
            case 1: cout << "Please enter a Milliamp Reading:";
                    cin >> currentma;
                    cout << "\nCalculating scaled value if mA reading is" << currentma <<" for you\n";
                    ans1a = marange / 16;  //this will equal 6.25 for 100
                    ans1 = ans1a * (currentma-4);
                    cout << "\nThe scaled value would be" << ans1 << engunit <<" for a given milliamp input of" << currentma <<".\n\n";
                        break;
            case 2: cout << "Please enter a Scaled Value:";
                    cin >> scaledval;
                    cout << "Calculating mA reading if scaled value is\n" << scaledval <<" for you\n";
                    ans2 = marange / 16;
                    ans2a = scaledval / (ans2+4); //* 10);
                    cout << "The scaled value would be" << std::setprecision(4) << ans2a << "mA for a scaled value of" << scaledval << ".\n\n";
                        break;
            default: cout << "Invalid Response";
            }
            if (mainchoice = 2)
            {//Sub routine for Flow calculations
                cout << "\t\tPlease choose an engineering unit\n\n";
                cout << "\t\t1: Litres per second ( L/s )\n";
                cout << "\t\t2: \n";
                cout << "\t\t3: \n";
                cout << "\t\t4: \n";
                cout << "\t\t5: \n";
                cout << "\t\t6: \n";
                cin >> engunita;
                
                switch (engunita)
                    {
                    case 1: cout << " Please enter a L/s reading:";
                            cin >> flowval1;
                            lpstolpm = flowval1 * 60; 
                            lpstolph = flowval1 * 3600; 
                            lpstomcph = flowval1 * 3.6; 
                            lpstomcpd = flowval1 * 86.4; 
                            lpstomld = flowval1 * 0.0864; 
                            cout << "\n "<< flowval1 <<"  = " << lpstolpm <<"L/min";
                            cout << "\n "<< flowval1 <<"   = " << lpstolph <<"L/hour";
                            cout << "\n "<< flowval1 <<"   = " << lpstomcph <<"m3/h";
                            cout << "\n "<< flowval1 <<"   = " << lpstomcpd <<"m3/d";
                            cout << "\n "<< flowval1 <<"   = " << lpstomld <<"ML/D";
                                break;
                    case 2: cout << " Please enter a L/m reading:";
                            cin >> flowval1;
                            lpmtolps = flowval1 / 60; 
                            lpmtolph = flowval1 * 60; 
                            lpmtomcph = flowval1 * 0.06; 
                            lpmtomcpd = flowval1 * 1.44; 
                            lpmtomld = flowval1 * 0.00144; 
                            cout << "\n "<< flowval1 <<"  = " << lpmtolps <<"L/sec";
                            cout << "\n "<< flowval1 <<"   = " << lpstolph <<"L/hour";
                            cout << "\n "<< flowval1 <<"   = " << lpstomcph <<"m3/h";
                            cout << "\n "<< flowval1 <<"   = " << lpstomcpd <<"m3/d";
                            cout << "\n "<< flowval1 <<"   = " << lpstomld <<"ML/D";
                                break;
                    case 3: cout << " Please enter a L/h reading:";
                            cin >> flowval1;
                            lphtolps = flowval1 * 60;
                            lphtolpm = flowval1 * 3600;
                            lphtomcph = flowval1 * 3.6; 
                            lphtomcpd = flowval1 * 86.4; 
                            lphtomld = flowval1 * 0.0864; 
                            cout << "\n "<< flowval1 <<"  = " << lphtolps <<"L/sec";
                            cout << "\n "<< flowval1 <<"   = " << lpstolpm <<"L/hour";
                            cout << "\n "<< flowval1 <<"   = " << lpstomcph <<"m3/h";
                            cout << "\n "<< flowval1 <<"   = " << lpstomcpd <<"m3/d";
                            cout << "\n "<< flowval1 <<"   = " << lpstomld <<"ML/D";
                                break;
                    default:cout << "Invalid Reponse" <<;
                }
            }
            else
            {
            } 
        }       
        cout << "\n\n\n\nPress any key to continue.\n";
        getch();
        return 0;
        }
Peter87 (11179)
I don't see any problem with line 57 but on line 163 you have nothing between << and the semicolon. If you don't want to print anything more than "Invalid Reponse" you should remove the <<.
Last edited on
Sausage (55)
Line 163 - default:cout << "Invalid Reponse" <<;
Also add #include <string> to the rest of your directives.
Line 171 - getch() is deprecated, use _getch.
You could use more precision, use double. If not, the compiler will moan about it.

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#include <cstdlib>
#include <iostream>
#include <conio.h>
#include <iomanip>
#include <string>

using namespace std;

int main()
{

	//Assigning variables
	int mainchoice = 0; //menu option
	//4-20mA Sub Routine
	string engunit;
	float marange = 0;
	float currentma = 0;
	float scaledval = 0;
	int maorscaled = 0;
	float ans1 = 0;
	float ans1a = 0;
	float ans2 = 0;
	double ans2a = 0; //NOT WORKING AT PRESENT

	//Flow Sub Routine
	int engunita = 0;
	int engunitb = 0;
	float flowval1 = 0;

	//Flow Tags
	double lpstolpm = 0;
	double lpstolph = 0;
	double lpstomcph = 0;
	double lpstomcpd = 0;
	double lpstomld = 0;

	double lpmtolps = 0;
	double lpmtolph = 0;
	double lpmtomcph = 0;
	double lpmtomcpd = 0;
	double lpmtomld = 0;

	double lphtolps = 0;
	double lphtolpm = 0;
	double lphtomcph = 0;
	double lphtomcpd = 0;
	double lphtomld = 0;


	cout << " Main Menu\n\n";
	cout << "\t\t1 - 4-20mA\n";
	cout << "\t\t2 - Flow\n";
	cout << "\t\t3 - \n";
	cout << "\t\t4 - \n";
	cout << "\t\t5 - \n";
	cout << "\t\t6 - \n";
	cout << "\t\t7 - \n";
	cout << "\t\t8 - \n";


	cout << "\n Please select which calculator: ";
	cin >> mainchoice;

	switch (mainchoice)
	{
	case 1: 
		cout << "\n4-20mA\n\n\n";
		break;
	case 2: 
		cout << "\nFlow.\n";
		break;
	case 3: 
		cout << "\nTime.\n";
		break;
	case 4: 
		cout << "\nOvercurrent i2t.\n";
		break;
	case 5: 
		cout << "\nCT Wire Size.\n";
		break;
	case 6:
		cout << "\nWet Well Volume.\n";
		break;
	case 7: 
		cout << "\nPercentage.\n";
		break;
	case 8: 
		cout << "\nThree Phase.\n";
		break;
	default: 
		cout << "\nInvalid Response.\n";
	}

	if (mainchoice = 1)
	{ //Sub routine for 4-20mA
		cout << "Please enter an engneering unit: ";
		cin >> engunit;
		cout << "\nPlease enter the range of the instrument: ";
		cin >> marange;
		cout << "\nChoose to enter either a milliamp reading or scaled";
		cout << " value, make your choice.\n\n\t\t1. Milliamp reading.\n\t\t2. Scaled Value\n";
		cin >> maorscaled;
		switch (maorscaled)
		{
		case 1: 
			cout << "Please enter a Milliamp Reading:";
			cin >> currentma;
			cout << "\nCalculating scaled value if mA reading is" << currentma << " for you\n";
			ans1a = marange / 16;  //this will equal 6.25 for 100
			ans1 = ans1a * (currentma - 4);
			cout << "\nThe scaled value would be" << ans1 << engunit << " for a given milliamp input of" << currentma << ".\n\n";
			break;
		case 2: 
			cout << "Please enter a Scaled Value:";
			cin >> scaledval;
			cout << "Calculating mA reading if scaled value is\n" << scaledval << " for you\n";
			ans2 = marange / 16;
			ans2a = scaledval / (ans2 + 4); //* 10);
			cout << "The scaled value would be" << std::setprecision(4) << ans2a << "mA for a scaled value of" << scaledval << ".\n\n";
			break;
		default: 
			cout << "Invalid Response";
		}
		if (mainchoice = 2)
		{//Sub routine for Flow calculations
			cout << "\t\tPlease choose an engineering unit\n\n";
			cout << "\t\t1: Litres per second ( L/s )\n";
			cout << "\t\t2: \n";
			cout << "\t\t3: \n";
			cout << "\t\t4: \n";
			cout << "\t\t5: \n";
			cout << "\t\t6: \n";
			cin >> engunita;

			switch (engunita)
			{
			case 1: 
				cout << " Please enter a L/s reading:";
				cin >> flowval1;
				lpstolpm = flowval1 * 60;
				lpstolph = flowval1 * 3600;
				lpstomcph = flowval1 * 3.6;
				lpstomcpd = flowval1 * 86.4;
				lpstomld = flowval1 * 0.0864;
				cout << "\n " << flowval1 << "  = " << lpstolpm << "L/min";
				cout << "\n " << flowval1 << "   = " << lpstolph << "L/hour";
				cout << "\n " << flowval1 << "   = " << lpstomcph << "m3/h";
				cout << "\n " << flowval1 << "   = " << lpstomcpd << "m3/d";
				cout << "\n " << flowval1 << "   = " << lpstomld << "ML/D";
				break;
			case 2: 
				cout << " Please enter a L/m reading:";
				cin >> flowval1;
				lpmtolps = flowval1 / 60;
				lpmtolph = flowval1 * 60;
				lpmtomcph = flowval1 * 0.06;
				lpmtomcpd = flowval1 * 1.44;
				lpmtomld = flowval1 * 0.00144;
				cout << "\n " << flowval1 << "  = " << lpmtolps << "L/sec";
				cout << "\n " << flowval1 << "   = " << lpstolph << "L/hour";
				cout << "\n " << flowval1 << "   = " << lpstomcph << "m3/h";
				cout << "\n " << flowval1 << "   = " << lpstomcpd << "m3/d";
				cout << "\n " << flowval1 << "   = " << lpstomld << "ML/D";
				break;
			case 3: 
				cout << " Please enter a L/h reading:";
				cin >> flowval1;
				lphtolps = flowval1 * 60;
				lphtolpm = flowval1 * 3600;
				lphtomcph = flowval1 * 3.6;
				lphtomcpd = flowval1 * 86.4;
				lphtomld = flowval1 * 0.0864;
				cout << "\n " << flowval1 << "  = " << lphtolps << "L/sec";
				cout << "\n " << flowval1 << "   = " << lpstolpm << "L/hour";
				cout << "\n " << flowval1 << "   = " << lpstomcph << "m3/h";
				cout << "\n " << flowval1 << "   = " << lpstomcpd << "m3/d";
				cout << "\n " << flowval1 << "   = " << lpstomld << "ML/D";
				break;
			default:
				cout << "Invalid Reponse";
			}
		}
		else
		{
		}
	}
	cout << "\n\n\n\nPress any key to continue.\n";
	_getch();
	return 0;
}
Last edited on
OspreyR10A (4)
Thank you Peter87 and Sausage. Line 163 fixed which has got rid of the error.
Also changed the data types of the suggested tags to doubles which will help. However the problem with the menu still persists. Have I made a mistake with the nested if do you think, because it still ignores the menu choice and goes through the first sub routine. Should I try using a number of do while loops to achieve this instead?
coder777 (8439)
line 94/124: it's an assignment. Use == for comparison: (mainchoice == 2)
Peter87 (11179)
Note the difference between = and ==.
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