C++ 上的整数验证

发布于 2024-12-09 11:20:41 字数 691 浏览 1 评论 0原文

我编写了小型 C++ 控制台应用程序，这是源代码：

#include<stdio.h>
#include<locale.h>
#include<ctype.h>
#include<stdlib.h>

void main()
{
    setlocale(LC_ALL, "turkish");
    int a,b,c,d;

    printf("first number: ");
    scanf("%d", &a);

    printf("second number: ");
    scanf("%d", &b);

    c = a+b;

    printf("Sum: : %d\n", c);
}

如您所见，我向用户请求两个数字，然后将它们相加。但我想添加一个控件，其中用户输入的检查号码是整数？

我将检查用户输入的数字，如果数字不是真正的整数，我将回显错误。我在每次 scanf 之后使用它，但效果不是很好。

if(!isdigit(a))
{
            printf("Invalid Char !");
            exit(1);
}

不久之后，在 scanf 操作中，如果用户键入“a”，它将产生一条错误消息并且程序停止工作。如果用户输入数字程序将继续

原文

I have written small C++ console application and this is source code :

#include<stdio.h>
#include<locale.h>
#include<ctype.h>
#include<stdlib.h>

void main()
{
    setlocale(LC_ALL, "turkish");
    int a,b,c,d;

    printf("first number: ");
    scanf("%d", &a);

    printf("second number: ");
    scanf("%d", &b);

    c = a+b;

    printf("Sum: : %d\n", c);
}

As you can see i'm requesting two numbers from user and than summing them. But i want to add a control which check number who enterede by user is integer?

I'll check number which typed by user and than if number isn't really a integer i will echo an error. I'm using this after every scanf but it's not working very well.

if(!isdigit(a))
{
            printf("Invalid Char !");
            exit(1);
}

In shortly, on a scanf action, if user type "a" it will produce an error message and program stop working. If user type a number program will continue

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冰雪之触 2024-12-16 11:20:41

scanf 会为您进行验证。只需检查 scanf 的返回值即可。

printf("first number: ");
if(scanf("%d", &a) != 1) {
  printf("Bad input\n");
  return 1;
}

printf("second number: ");
if(scanf("%d", &b) != 1) {
  printf("Bad input\n");
  return 1;
}

scanf does that validation for you. Just check the return value from scanf.

printf("first number: ");
if(scanf("%d", &a) != 1) {
  printf("Bad input\n");
  return 1;
}

printf("second number: ");
if(scanf("%d", &b) != 1) {
  printf("Bad input\n");
  return 1;
}

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杀手六號 2024-12-16 11:20:41

执行此操作的 C++ 方法是

#include <iostream>
#include <locale>

int main()
{
    std::locale::global(std::locale("nl_NL.utf8")); // tr_TR doesn't exist on my system

    std::cout << "first number: ";

    int a;
    if (!(std::cin >> a))
    {
        std::cerr << "whoops" << std::endl;
        return 255;
    }

    std::cout << "second number: ";

    int b;
    if (!(std::cin >> b))
    {
        std::cerr << "whoops" << std::endl;
        return 255;
    }

    int c = a+b;

    std::cout << "Sum: " <<  c << std::endl;

    return 0;
}

The C++ way to do this would be

#include <iostream>
#include <locale>

int main()
{
    std::locale::global(std::locale("nl_NL.utf8")); // tr_TR doesn't exist on my system

    std::cout << "first number: ";

    int a;
    if (!(std::cin >> a))
    {
        std::cerr << "whoops" << std::endl;
        return 255;
    }

    std::cout << "second number: ";

    int b;
    if (!(std::cin >> b))
    {
        std::cerr << "whoops" << std::endl;
        return 255;
    }

    int c = a+b;

    std::cout << "Sum: " <<  c << std::endl;

    return 0;
}

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