如何擺脫此錯誤：「MSVCRTD.lib（crtexe.obj）：錯誤LNK2019：無法解析的外部符號_main在函數中引用___tmainCRTStartup」

Question

我幫她的C++的朋友，但說實話，我們需要一個大量的幫助。

爲什麼我們總是得到這個錯誤： 「MSVCRTD.LIB（crtexe.obj）：錯誤LNK2019：無法解析的外部 符號主函數引用_ _tmainCRTStartup」

的代碼如下：

//Maria Delgado (1013725) - Coursework 2 - Program Conducting timber component structural design 
#include<iostream> 
#include<iomanip> 
#include<cmath> 
#include<fstream> 
#include<string> 
using namespace std; 
//Variables for Strength Properties in (N/mm2) 
//fmk=Bending 
//fc90k=Compression Perpendicular 
//fvk=Shear 

//Calculating Member Size Factor: 
void memberSizeFactor(double chosenDepth) 
{ 
    if (chosenDepth<150) 
     kH=pow(150/chosenDepth,0.2); 
    else 
     cout<<"Please input a depth less than 150mm"<<endl; 
} 

//Error message for all negative values entered 
double errorNeg() 
{ 
float value=-1; 
while (value<0) 
{ 
    cout<<"You have entered a negative value. This variable cannot take negative values. Please input positive values!"; 
    cin>>value; 
    cout<<endl; 
} 
return value; 
} 

//Beam Member Class 
class beamMember 
{ 
private: 
double chosenLength; 
double chosenWidth; 
double chosenDepth; 
double chosenBearingLength; 
double serviceClassAbility; 
string strengthClass; 
public: 
beamMember() 
{ 
    chosenLength=chosenWidth=chosenDepth=chosenBearingLength=serviceClassAbility=0; 

    strengthClass=""; 
} 

void beamDimensionsData() 
{ 
    cout<<"The following dimensions need to be input into the program:"<<endl; 

    cout<<"What is the desired beam LENGTH in millimeters?"; 
    cin>>chosenLength; 
    if(chosenLength<0) chosenLength=errorNeg(); 

    cout<<"What is the desired beam WIDTH in millimeters?"; 
    cin>>chosenWidth; 
    if(chosenWidth<0) chosenWidth=errorNeg(); 

    cout<<"What is the desired beam DEPTH in millimeters?"; 
    cin>>chosenDepth; 
    if(chosenDepth<0) chosenDepth=errorNeg(); 

    cout<<"What is the desired beam BEARING LENGTH in millimeters?"; 
    cin>>chosenBearingLength; 
    if(chosenBearingLength<0) chosenBearingLength = errorNeg(); 

    cout<<"Please insert a strength class of timber e.g.C12 to C50:"; 
    cin>>strengthClass; 

    cout<<endl<<"Please choose a service class ability for member i.e. 1 or 2 or 3:"; 
    cin>>serviceClassAbility; 

    cout<<endl; 
} 


//***************************CALCULATE OVERALL DESIGN LOAD************************************************************ 
double load(beamMember designBeam) 
{ 
    cout<<"Under these circumstances, the beam will be adequate to support a slab."<<endl<<endl; 
    double qK; 
    double gK; 
    double span; 

    cout<<"Please input the total live load in kN/m2:"; 
    cin>>qK; 
    cout<<endl; 
    if (qK<0) qK=errorNeg(); 
    qK=qK*gammaQ; 

    cout<<"Please input the total dead load in kN/m2:"; 
    cin>>gK; 
    if (gK<0) gK=errorNeg(); 
    gK=gK*gammaG; 

    cout<<"Enter the span between the beams in millimeters:"; 
    cin>>span; 
    while(span<0) span=errorNeg(); 
    cout<<endl; 
    span=span*(qK+gK)*chosenLength/10e2; 
    cout<<"Point load:"<<span<<"N"<<endl<<endl; 
    return span; 
} 

//***********************************CHECKING BENDING STRESS********************************************************* 
void checkBendingStress(beamMember designBeam, double force) 
{ 
    cout<<"Bending Stress Check:"<<endl; 
    double bendingMoment; 
    double secondMomentofArea; 
    double designBendingStress; 
    double actualBendingStress; 

    bendingMoment=force*chosenLength/8; 
    cout<<"Maximum bending moment is "<<bendingMoment<<"Nmm"<<endl; 

    secondMomentofArea=chosenWidth*pow(chosenDepth,3)/12; 

    designBendingStress=kH*kSYS*kMOD*matrix[0]/gammaM; 
    actualBendingStress=(bendingMoment*chosenDepth/2)/secondMomentofArea; 

    cout<<"Maximum permissibile stress:"<<designBendingStress<<"N/mm2"<<endl; 
    cout<<"The actual stress that the beam is subject to:"<<actualBendingStress<<"N/mm2"<<endl; 

    if(actualBendingStress<=designBendingStress) 
    cout<<"Beam bending stress check successful!"<<endl<<endl; 
    else 
    cout<<"Beam bending stress check unnsuccessful!"<<endl<<endl; 
} 

//***********************************CHECKING SHEAR STRESS********************************************************* 
void checkShearStress(beamMember designBeam, double force) 
{ 
    cout<<"Shear Stress Check:"<<endl; 
    double designShearingStress; 
    double actualShearingStress; 

    designShearingStress=matrix[5]*kMOD*kSYS/gammaM; 
    actualShearingStress=(1.5*force/2)/(chosenWidth)/(chosenDepth); 
    cout<<"Maximum permissible shear stress:"<<designShearingStress<<"N/mm2"<<endl; 
    cout<<"Shear stress that the supports are subjected to:"<<actualShearingStress<<"N/mm2"<<endl; 
    if(actualShearingStress<=designShearingStress) 
    cout<<"Beam shear stress check successful!"<<endl<<endl; 
    else 
    cout<<"Beam shear stress check unsucessful!"<<endl<<endl; 
} 

//********************************CHECKING BEARING STRESS*********************************************************** 
void checkBearingStress(beamMember designBeam, double force) 
{ 
    double kc90; 
    double designBearingStress; 
    double actualBearingStress; 

    actualBearingStress=force/2/chosenWidth/chosenBearingLength; 
    cout<<"Bearing Stress that the beam is subjected to:"<<actualBearingStress<<"N/mm2"<<endl; 

    designBearingStress=matrix[4]*kMOD*kSYS/gammaM; 
    cout<<"Maximum permissible bearing stress:"<<designBearingStress<<"N/mm2"<<endl; 

    kc90=(2.38-chosenBearingLength/250)*(1+chosenDepth/12/chosenBearingLength); 
    cout<<"Constant, kc90 is "<<kc90<<endl; 
    cout<<"Factored design bearing stress is "<<kc90*designBearingStress<<endl; 

    if (actualBearingStress<=designBearingStress) 
    cout<<"Beam bearing stress check successful!"<<endl<<endl; 
    else 
    cout<<"Beam bearing stress check unsuccessful!"<<endl<<endl; 
} 

//********************************CHECKING LATERAL TORSIONAL STABILITY************************************************** 
void checkLateralTorsionalStability(beamMember designBeam, double force) 
{ 
    cout<<"Lateral Torsional Stability Check:"<<endl; 

    double bendingMoment; 
    double secondMomentofArea; 
    double designBendingStress; 
    double actualBendingStress; 

    bendingMoment=force*chosenLength/8; 
    cout<<"Maximum bending moment is "<<bendingMoment<<"Nmm"<<endl; 

    secondMomentofArea=chosenWidth*pow(chosenDepth,3)/12; 

    designBendingStress=kH*kSYS*kMOD*matrix[0]/gammaM; 
    actualBendingStress=(bendingMoment*chosenDepth/2)/secondMomentofArea; 

    cout<<"Maximum permissibile stress:"<<designBendingStress<<"N/mm2"<<endl; 
    cout<<"The actual stress that the beam is subject to:"<<actualBendingStress<<"N/mm2"<<endl; 

    if(actualBendingStress<=designBendingStress) 
    cout<<"Beam Lateral Torsional Stability check successful!"<<endl<<endl; 
    else 
    cout<<"Beam Lateral Tosional Stability check unnsuccessful!"<<endl<<endl; 
} 

//*************************************FUNCTION FOR STRENGTH CLASS DATA FILE********************************************** 
void strengthClassData(string classStrength, double serviceClass) 
{ 
    string data; 
    ifstream file; 
    file.open("strengthclassdata.txt"); 
    file>>data; 
    while(file&&data!=classStrength) 
    { 
    file>>data; 
    } 
    for(int i=0;i<=5;i++) 
    file>>matrix[i]; 
    file.close(); 
} 

//Welcome Message for Program 
void welcome() 
{ 
cout<<"The following is Yadhuvamshi Rajamani's program"<<endl 
    <<"that conducts timber component structural design"<<endl 
    <<"according to EC5. Specifically, it is a limit state"<<endl 
    <<"design program that compares design actions with design strengths."<<endl; 
} 

//******************************BEAM START UP***************************************************************************** 
void beamStartUp() 
{ 
    beamMember designBeam; 
    double force; 
    designBeam.beamDimensionsData(); 
    force=load(designBeam); 
    checkBendingStress(designBeam,force); 
    checkShearStress(designBeam,force); 
    checkBearingStress(designBeam,force); 
    checkLateralTorsionalStability(designBeam,force); 
} 

int main() 
{ 
    welcome(); 
    char startKey; 
    cout<<"Please select 1 to start the beam test program or 2 to exit the program, followed by enter!"; 
    cin>>startKey; 
    cout<<endl; 
    while(startKey!='2') 
    { 
    switch(startKey) 
    { 
    case '2': 
    return 1; 
    case '1': 
    beamStartUp(); 
    break; 
    } 
    cout<<"Please select 1 to start the beam test program or 2 to exit the program, followed by enter!"; 
    cin>>startKey; 
    cout<<endl; 
    } 
return 1; 
} 
}; 

` 

Answer 1

int main()功能需要超出您的類定義。您將需要創建一個類實例並使用它來調用welcome和beamStartUp函數。

Answer 2

我找到了一個鏈接，可以幫助：

http://mihirknows.blogspot.com/2009/06/error-1-error-lnk2019-unresolved.html