在制作计算器时,if-statement比什么更好

时间:2015-12-15 06:53:40

标签: c if-statement

我试图创建一个程序,在显示总价时计算所选食物的价格。我已经可以计算并显示总价。我的问题是每当用户输入" [3]退出"并且他选择" [1]重置",程序中断并检测到许多错误。我想知道我的程序应该使用哪种更好的声明。谢谢!

void PriceCalculator(){
    system("cls");
    char yn[3];
    int choice;

    float spinachP=7.18;    
    float romaineP=12.21;
    float mustardP=11.18;
    float carrotsP=1.6;
    float potatoP=1.0;
    float yamP=2.1;
    float asparagusP=15.98;
    float brocolliP=10.65;
    float melonP=8.31;
    float strawberryP=10.62;

    float spinach=0;
    float romaine=0;
    float mustard=0;
    float carrots=0;
    float potato=0;
    float yam=0;
    float asparagus=0;
    float brocolli=0;
    float melon=0;
    float strawberry=0;

    float spinachT=0;
    float romaineT=0;
    float mustardT=0;
    float carrotsT=0;
    float potatoT=0;
    float yamT=0;
    float asparagusT=0;
    float brocolliT=0;
    float melonT=0;
    float strawberryT=0;

    float totalSpi=0;
    float totalRom=0;   
    float totalMus=0;
    float totalCar=0;
    float totalPot=0;
    float totalYam=0;
    float totalAsp=0;
    float totalBro=0;
    float totalMel=0;
    float totalStr=0;

    float totalP=0;

    do{
        border();
        gotoxy(50, 5); p("Budget Calculator");
        totalP=totalSpi+totalRom+totalMus+totalCar+totalPot+totalYam+totalAsp+totalBro+totalMel+totalStr;\                                                          
        gotoxy(50, 7); p("Total Price : P %.2f", totalP);
        gotoxy(5, 5); p("[1] Spinach\t=\tP %.2f", totalSpi);
        gotoxy(5, 6); p("[2] Romaine\t=\tP %.2f", totalRom);
        gotoxy(5, 7); p("[3] Mustard\t=\tP %.2f", totalMus);
        gotoxy(5, 8); p("[4] Carrots\t=\tP %.2f", totalCar);
        gotoxy(5, 9); p("[5] Potato\t\t=\tP %.2f", totalPot);
        gotoxy(5, 10); p("[6] Yam\t\t=\tP %.2f", totalYam);
        gotoxy(5, 11); p("[7] Asparagus\t=\tP %.2f", totalAsp);
        gotoxy(5, 12); p("[8] Brocolli\t=\tP %.2f", totalBro);
        gotoxy(5, 13); p("[9] Melon\t\t=\tP %.2f", totalMel);
        gotoxy(5, 14); p("[10] Strawberry\t=\tP %.2f", totalStr);
        gotoxy(5, 15); p("[11] Exit");

        gotoxy(5, 17); p("Enter Choice: ");
        s("%d",&choice);

    if(choice == 1){
    gotoxy(5, 19); p("How many grams of Spinach? ");
    s("%f",&spinach);
    if(spinach < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    spinachT=(spinach/20)*spinachP;
    totalSpi += spinachT;
    gotoxy(5, 20); p("Price: P %.2f",spinachT);

    gotoxy(5, 21); p("Enter again (y/n)?");
    s("%s", &yn);
    if(strcmp(yn, "y")==0){
        system("cls");

    }else if(strcmp(yn, "n")){
        break;
    }

    }
    }
    else if(choice == 2){
    gotoxy(5, 19); p("How many grams of Romain Lettuce? ");
    s("%f",&romaine);
    if(romaine < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    romaineT=(romaine/20)*romaineP;
    totalRom += romaineT;
    gotoxy(5, 20); p("Price: P %.2f",romaineT);

    gotoxy(5, 21); p("Enter again (y/n)?");
    s("%s", &yn);
    if(strcmp(yn, "y")==0){
        system("cls");

    }else if(strcmp(yn, "n")){
        break;
    }

    }
    }
    else if(choice == 3){
    gotoxy(5, 19); p("How many grams of Mustard Greens? ");
    s("%f",&mustard);
    if(mustard < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    mustardT=(mustard/20)*mustardP;
    totalMus += mustardT;
    gotoxy(5, 20); p("Price: P %.2f",mustardT);
    }
    }
    else if(choice == 4){
    gotoxy(5, 19); p("How many grams of Carrots? ");
    s("%f",&carrots);
    if(carrots < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    carrotsT=(carrots/20)*carrotsP;
    totalCar += carrotsT;
    gotoxy(5, 20); p("Price: P %.2f",carrotsT);
    }
    }
    else if(choice == 5){
    gotoxy(5, 19); p("How many grams of Potato? ");
    s("%f",&potato);
    if(potato < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    potatoT=(potato/20)*potatoP;
    totalPot += potatoT;
    gotoxy(5, 20); p("Price: P %.2f",potatoT);
    }
    }
    else if(choice == 6){
    gotoxy(5, 19); p("How many grams of Yam? ");
    s("%f",&yam);
    if(yam < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    yamT=(yam/20)*yamP;
    totalPot += yamT;
    gotoxy(5, 20); p("Price: P %.2f",yamT);
    }
    }
    else if(choice == 7){
    gotoxy(5, 19); p("How many grams of Asparagus? ");
    s("%f",&asparagus);
    if(asparagus < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    asparagusT=(asparagus/20)*asparagusP;
    totalAsp += asparagusT;
    gotoxy(5, 20); p("Price: P %.2f",asparagusT);
    }
    }
    else if(choice == 8){
    gotoxy(5, 19); p("How many grams of Brocolli? ");
    s("%f",&brocolli);
    if(brocolli < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    brocolliT=(brocolli/20)*brocolliP;
    totalBro += brocolliT;
    gotoxy(5, 20); p("Price: P %.2f",brocolliT);
    }
    }
    else if(choice == 9){
    gotoxy(5, 19); p("How many grams of Melon? ");
    s("%f",&melon);
    if(melon < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    melonT=(melon/20)*melonP;
    totalMel += melonT;
    gotoxy(5, 20); p("Price: P %.2f",melonT);
    }
    }
    else if(choice == 10){
    gotoxy(5, 19); p("How many grams of Strawberry? ");
    s("%f",&strawberry);
    if(strawberry < 0){
        gotoxy(5, 20); p("Error! Invalid input.");
    }else{
    strawberryT=(strawberry/20)*strawberryP;
    totalStr += strawberryT;
    gotoxy(5, 20); p("Price: P %.2f",strawberryT);
    }
    }

    else if(choice == 11){
    gotoxy(5, 19); p("[1] Reset [2] Back to Home");
    gotoxy(5, 20); p("Enter choice: "); 
    s("%d", &choice);


    if(choice = 1){
        totalP=0;

        spinachT=0;
        romaineT=0;
        mustardT=0;
        carrotsT=0;
        potatoT=0;
        yamT=0;
        asparagusT=0;
        brocolliT=0;
        melonT=0;
        strawberryT=0;

        totalSpi=0;
        totalRom=0;
        totalMus=0;
        totalCar=0;
        totalPot=0;
        totalYam=0;
        totalAsp=0;
        totalBro=0;
        totalMel=0;
        totalStr=0;

        system("cls");
    }

    else if(choice == 2){
        break;  
    }

    }
    if(choice < 1 || choice > 12){
    gotoxy(5, 19); p("Error! Please choose between 1-10.");
    }
    }while(choice != 0);
    }

2 个答案:

答案 0 :(得分:1)

使用if-elseswitch语句。否则,将根据您的代码段评估和检查每个if条件。

答案 1 :(得分:1)

您的代码中有拼写错误:

else if(choice == 11){
    // some code...
    if(choice = 1){ // you miss a "=" here!!!
        // more code...
    }

    else if(choice == 2){
        break;  

    }

}

结果如下:

if(choice = 1)

这会将选项分配给1,之后它将检查选项是否大于0.这将始终为真。下一个分支

else if(choice == 2)

永远不会被执行。

PS:如果您下次提出问题,请包含问题的正确和完整描述。

  

程序中断并检测到许多错误

没有问题的描述。 此外,如果您已经调试了行,或者包含了一些跟踪消息,您会立即注意到您的程序流程不符合预期。