為什么我得到正確的輸出，但它也顯示程式2和3的ifelse輸出

這是一個入學計劃，每個計劃都有一定的條件

//The front
cout<<"Welcome to admission system"<<"\n";
cout<<"---------------------------"<<"\n";
cout<<"Admission open for year 2022"<<"\n";
cout<<"Press 1 for BSc Electrical Engineering Department"<<"\n";
cout<<"Press 2 for BSc Mechanical Engineering Department"<<"\n";
cout<<"Press 3 for MSc Mechanical Engineering Department"<<"\n";

//Personal details
cout<<"Your personal details"<<"\n";
cout<<"---------------------"<<"\n";
cout<<"Enter your Civil ID:";
cin>>civil_no;
cout<<"Enter your Name: ";
cin>>name;
cout<<"Enter Age: "<<"\n";
cin>>age;
cout<<"Enter contact Number: ";
cin>>phone;
cout<<"Enter program applying for: ";
cin>>pg; //pg here is meant as the department the user want to choose 

//Education details
cout<<"Education Details"<<"\n";
cout<<"-----------------"<<"\n";
cout<<"Enter Applicant highest qualification passing years:";
//cin>>year_of_passing;
cout<<"Enter Qualification Passing Year:";
//cin>>qualification;
cout<<"Enter Obtained marks (%):";
//cin>>marks;


//Program 1
if (pg==1 && marks>=60 && qualification==12) {
    cout<<"You are fully eligible for this program1"<<"\n";
}
else if(pg==1 || marks<60 || qualification!=12){
    cout<<"you are not eligible 1"<<"\n";
}


//Program 2
if (pg==2 && marks>=65 && qualification==12) {
    cout<<"You are fully eligible for this program 2"<<"\n";
}
else if(pg==2 || marks<65 || qualification!=12){
    cout<<"you are not eligible 2"<<"\n";
}


//Program 3
if (pg==3 && marks>=70 && qualification==14) {
    cout<<"You are fully eligible 3"<<"\n";
}
else if(pg==3 || marks<70 || qualification!=14){
    cout<<"you are not eligible 3"<<"\n";
}

uj5u.com熱心網友回復：

if else 陳述句的集合不正確。例如，如果您輸入的限定值不等于 12，則所有三個 else 陳述句都將被執行，因為條件qualification!=12在所有三個 else 陳述句中都為真。

你需要寫

//Program 1
if (pg==1 && marks>=60 && qualification==12) {
    cout<<"You are fully eligible for this program1"<<"\n";
}
else if(pg==1 && ( marks<60 || qualification!=12 )){
    cout<<"you are not eligible 1"<<"\n";
}


//Program 2
if (pg==2 && marks>=65 && qualification==12) {
    cout<<"You are fully eligible for this program 2"<<"\n";
}
else if( pg==2 && ( marks<65 || qualification!=12 )){
    cout<<"you are not eligible 2"<<"\n";
}


//Program 3
if (pg==3 && marks>=70 && qualification==14) {
    cout<<"You are fully eligible 3"<<"\n";
}
else if( pg==3 && ( marks<70 || qualification!=14 ) ){
    cout<<"you are not eligible 3"<<"\n";
}

或者例如

//Program 1
if ( pg==1 )
{ 
    if ( marks>=60 && qualification==12) {
        cout<<"You are fully eligible for this program1"<<"\n";
    }
    else {
        cout<<"you are not eligible 1"<<"\n";
    }
}


//Program 2
if (pg==2 )
{
    if ( marks>=65 && qualification==12) {
        cout<<"You are fully eligible for this program 2"<<"\n";
    }
    else {
        cout<<"you are not eligible 2"<<"\n";
    }
}


//Program 3
if ( pg==3 )
{
    if ( marks>=70 && qualification==14) {
        cout<<"You are fully eligible 3"<<"\n";
    }
    else {
        cout<<"you are not eligible 3"<<"\n";
    }
}

uj5u.com熱心網友回復：

無論pg==1 還是2 或3，它總是可以進入其他兩個程式的else 條件。 例如，假設：pg == 1 并且標記 = 62 和資格 = 12，

1.進入程式1的if塊

//Program 1
if (pg==1 && marks>=60 && qualification==12) {
    cout<<"You are fully eligible for this program1"<<"\n";
}

2.進入程式2的else塊

else if(pg==2 || marks<65 || qualification!=12){
    cout<<"you are not eligible 2"<<"\n";
}

3.進入程式3的else塊

else if(pg==3 || marks<70 || qualification!=14){
    cout<<"you are not eligible 3"<<"\n";
}

這是因為在 else 塊中，你使用了or || 由于該條件，即使一個條件（在這種情況下為標記）結果為真，該塊也將執行！

標籤：C if 语句

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