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C++ C++;初学者-简单输出_C++ - Fatal编程技术网

C++ C++;初学者-简单输出

C++ C++;初学者-简单输出,c++,C++,这里我有一些简单的代码作为整数计算器 //Calculator, by Michael Lowry #include <iostream> using namespace std; void main () { int input = 0; int input2 = 0; int answer = 0; int operation = 0; cout << "Enter your first number" <<

这里我有一些简单的代码作为整数计算器

//Calculator, by Michael Lowry

#include <iostream>
using namespace std; 

void main ()
{
    int input = 0;
    int input2 = 0;
    int answer = 0;
    int operation = 0;

    cout << "Enter your first number" << endl;
    cin >> input;

    cout << "Type 1 for addition, 2 for subtraction, 3 for multiplication, or 4 for division" << endl;
    cin >> operation;

    cout << "Enter your second number" << endl;
    cin >> input2;

    if (operation = 1)
    {
        input + input2 == answer;
    }

    if (operation = 2)
    {
        input - input2 == answer;
    }

    if (operation = 3)
    {
        input * input2 == answer;
    }

    if (operation = 4)
    {
        input / input2 == answer;
    }

    cout << "Your answer is " <<
    cout << answer << endl;
    system ("PAUSE");
}
//计算器,作者:迈克尔·洛瑞
#包括
使用名称空间std;
空干管()
{
int输入=0;
int input2=0;
int-answer=0;
整数运算=0;
不能输入;
cout操作;
cout输入2;
如果(操作=1)
{
输入+输入2==答案;
}
如果(操作=2)
{
输入-输入2==答案;
}
如果(操作=3)
{
输入*输入2==答案;
}
如果(操作=4)
{
输入/输入2==答案;
}

cout有几个错误:这是
操作
变量指定一个值,而不是将其与以下内容进行比较:

if (operation = 1)
应该是这样

if(operation == 1)
answer = input + input2;
此外,这不会将
input+input2
的结果分配给答案,而是进行未使用的比较评估

input + input2 == answer;
应该是这样

if(operation == 1)
answer = input + input2;
您应该相应地更改代码。最后:

cout << "Your answer is " << 
cout << answer << endl;
另外:
main()
应该返回
int

因此,您的代码应该如下所示:

int main () {
    int input = 0;
    int input2 = 0;
    int answer = 0;
    int operation = 0;

    cout << "Enter your first number" << endl;
    cin >> input; 

    cout << "Type 1 for addition, 2 for subtraction, 3 for multiplication, or 4 for division" << endl;
    cin >> operation;

    cout << "Enter your second number" << endl; 
    cin >> input2;

    if (operation == 1) {
        answer = input + input2;
    }

    if (operation == 2) {
        answer = input - input2;
    }

    if (operation == 3) {
     answer = input * input2;
    }

    if (operation == 4) {
     answer = input / input2;
    }

    cout << "Your answer is " << answer << endl;
    system ("PAUSE");
}
int main(){
int输入=0;
int input2=0;
int-answer=0;
整数运算=0;
不能输入;
cout操作;
cout输入2;
如果(操作==1){
答案=输入+输入2;
}
如果(操作==2){
答案=输入-输入2;
}
如果(操作==3){
答案=输入*输入2;
}
如果(操作==4){
答案=输入/输入2;
}

cout有几个错误:这是
操作
变量指定一个值,而不是将其与以下内容进行比较:

if (operation = 1)
应该是这样

if(operation == 1)
answer = input + input2;
此外,这不会将
input+input2
的结果分配给答案,而是进行未使用的比较评估

input + input2 == answer;
应该是这样

if(operation == 1)
answer = input + input2;
您应该相应地更改代码。最后:

cout << "Your answer is " << 
cout << answer << endl;
另外:
main()
应该返回
int

因此,您的代码应该如下所示:

int main () {
    int input = 0;
    int input2 = 0;
    int answer = 0;
    int operation = 0;

    cout << "Enter your first number" << endl;
    cin >> input; 

    cout << "Type 1 for addition, 2 for subtraction, 3 for multiplication, or 4 for division" << endl;
    cin >> operation;

    cout << "Enter your second number" << endl; 
    cin >> input2;

    if (operation == 1) {
        answer = input + input2;
    }

    if (operation == 2) {
        answer = input - input2;
    }

    if (operation == 3) {
     answer = input * input2;
    }

    if (operation == 4) {
     answer = input / input2;
    }

    cout << "Your answer is " << answer << endl;
    system ("PAUSE");
}
int main(){
int输入=0;
int input2=0;
int-answer=0;
整数运算=0;
不能输入;
cout操作;
cout输入2;
如果(操作==1){
答案=输入+输入2;
}
如果(操作==2){
答案=输入-输入2;
}
如果(操作==3){
答案=输入*输入2;
}
如果(操作==4){
答案=输入/输入2;
}

你的输出出了问题。你应该

cout << "Your answer is " << answer << endl;

你的输出出错了,你应该

cout << "Your answer is " << answer << endl;
第一:使用

if (operation == 1)
而不是

cout << "Your answer is " << 
cout << answer << endl;
if (operation = 1)
input + input2 == answer;
因为
=
表示相等,
=
表示赋值

第二:

answer = input1 + input2;
而不是

cout << "Your answer is " << 
cout << answer << endl;
if (operation = 1)
input + input2 == answer;
在所有
if
语句中执行此操作

第三:使用

cout << "Your answer is "  << answer << endl;
cout首先:使用

if (operation == 1)
而不是

cout << "Your answer is " << 
cout << answer << endl;
if (operation = 1)
input + input2 == answer;
因为
=
表示相等,
=
表示赋值

第二:

answer = input1 + input2;
而不是

cout << "Your answer is " << 
cout << answer << endl;
if (operation = 1)
input + input2 == answer;
在所有
if
语句中执行此操作

第三:使用

cout << "Your answer is "  << answer << endl;
不能先出错
如果要将值分配给变量
应答
,应执行以下操作:

answer = input1 (required operator here) input2;
在您的代码中,这样的构造:

input - input2 == answer;
有两个方面是错误的:

  • 如果要分配值来回答,请使用分配
    =
    不比较
    =
    运算符
  • 赋值从右向左,因此所需变量应位于左侧
  • 第二个错误 在
    if(val=yourConstant)
    行中,您犯了一个非常常见的错误,即在if语句内部赋值。许多语言禁止这样做,因为在不进行调试或测试的情况下很难检测到。if语句内部的代码只有在
    yourConstant
    大于0时才会执行。请改用
    if(val==yourConstant)
    如果(yourConstant==val)
    第一个错误 如果要将值分配给变量
    应答
    ,应执行以下操作:

    answer = input1 (required operator here) input2;
    
    在您的代码中,这样的构造:

    input - input2 == answer;
    
    有两个方面是错误的:

  • 如果要分配值来回答,请使用分配
    =
    不比较
    =
    运算符
  • 赋值从右向左,因此所需变量应位于左侧
  • 第二个错误 在
    if(val=yourConstant)
    行中,您犯了一个非常常见的错误,即在if语句内部赋值。许多语言禁止这样做,因为在不进行调试或测试的情况下很难检测到。if语句内部的代码只有在
    yourConstant
    大于0时才会执行。请改用
    if(val==yourConstant)
    如果(yourConstant==val)

    那么,不要:

    if (operation = 1)
    
    做:

    同时将输出更改为:
    cout

    if (operation = 1)
    
    做:

    同时将输出更改为:
    cout-enable compiler warnings.enable compiler warnings.if值是常量,建议使用
    if(yourcontainst==val)
    编译器将帮助您轻松捕获错误如果值是常量,建议使用
    if(yourcontainst==val)
    编译器将帮助您更轻松地捕获错误