c - 即使满足所有循环和条件语句，我的 C 代码也会继续运行并且不会返回任何结果

Question

我也尝试过OnlineGBD调试工具和Visual Studio，但它们都没有多大帮助。

如果我输入“1 1 1 1 8”，程序仍然会运行并且不会返回所需的输出。

我研究了一下，网上有人说问题出在变量的三重声明上，但是我更改了每个函数的变量名称，问题仍然存在。

#include <stdio.h>

int IPAndSubnetMaskInput(int IPAndSubnetMaskFirstOctate, int IPAndSubnetMaskSecondOctate, int IPAndSubnetMaskThirdOctate, int IPAndSubnetMaskFourthOctate, int IPAndSubnetMaskSubnetInput) {

    printf("Please input an IPv4 address followed by the subnetmask (must either be 8, 16, 24, or 32) in the following format: 192 168 1 1 32: \n"); //Statement to ask for IP and submask input and puts the inputs into a variable to calculate Broadcast IP
    int IPv4AndSubmask = scanf("%d %d %d %d %d", &IPAndSubnetMaskFirstOctate, &IPAndSubnetMaskSecondOctate, &IPAndSubnetMaskThirdOctate, &IPAndSubnetMaskFourthOctate, &IPAndSubnetMaskSubnetInput); //Input function

    while (!(IPAndSubnetMaskSubnetInput == 8 || IPAndSubnetMaskSubnetInput == 16 || IPAndSubnetMaskSubnetInput == 24 || IPAndSubnetMaskSubnetInput == 32)) { //Initializing loop to evaluate whether subnet is correct or not

        printf("Your submask is wrong. Please enter a value that's either 8, 16, 24, or 32: \n");
        scanf("%d", &IPAndSubnetMaskSubnetInput);

    if (IPAndSubnetMaskSubnetInput == 8 || IPAndSubnetMaskSubnetInput == 16 || IPAndSubnetMaskSubnetInput == 24 || IPAndSubnetMaskSubnetInput == 32)
        { break; }
    }
    return IPv4AndSubmask;//function returns the value of IP octates and the subnet mask for the program to calculate
}


int broadcastCalculator(int broadcastFirstOctate, int broadcastSecondOctate, int broadcastThirdOctate, int broadcastFourthOctate, int broadcastSubnetInput) { //Declaration of first function for first Assignment point

    IPAndSubnetMaskInput(broadcastFirstOctate, broadcastSecondOctate, broadcastThirdOctate, broadcastFourthOctate, broadcastSubnetInput);

    while (0 == 0) {
        if (broadcastSubnetInput == 8) { //Conditional statement for submask of 8
            printf("The broadcast IP is:\t%hhu\t%hhu\t%hhu\t255\t\n", broadcastFirstOctate, broadcastSecondOctate, broadcastThirdOctate);//Program will print the Broadcast IP of firstOctate  secondOctate thirdOctate 255
            break;
        }
        else if (broadcastSubnetInput == 16) {//Conditional statement for submask of 16
            printf("The broadcast IP is:\t%hhu\t%hhu\t255\t255\t\n", broadcastFirstOctate, broadcastSecondOctate);//Program will print the Broadcast IP of firstOctate  secondOctate 255 255
            break;
        }
        else if (broadcastSubnetInput == 24) {//Conditional statement for submask of 24
            printf("The broadcast IP is:\t%hhu\t255\t255\t255\t\n", broadcastFirstOctate);//Program will print the Broadcast IP of firstOctate  255 255 255
            break;
        }
        else if (broadcastSubnetInput == 32) {//Conditional statement for submask of 32
            printf("The broadcast IP is:\t255\t255\t255\t255");//Program will print the Broadcast IP of 255  255 255 255
            break;
        }

    }
    return 0;
}


int main()
{
    int firstOctate, secondOctate, thirdOctate, fourthOctate, subnetInput;
    broadcastCalculator(firstOctate, secondOctate, thirdOctate, fourthOctate, subnetInput);

    return 0;
}

Answer 1

编译发布的代码时:

gcc    -ggdb -Wall -Wextra -Wconversion -pedantic -std=gnu11  -c "untitled2.c"  
untitled2.c: In function ‘main’:
untitled2.c:50:5: warning: ‘firstOctate’ is used uninitialized in this function [-Wuninitialized]
     broadcastCalculator(firstOctate, secondOctate, thirdOctate, fourthOctate, subnetInput);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
untitled2.c:50:5: warning: ‘secondOctate’ is used uninitialized in this function [-Wuninitialized]
untitled2.c:50:5: warning: ‘thirdOctate’ is used uninitialized in this function [-Wuninitialized]
untitled2.c:50:5: warning: ‘fourthOctate’ is used uninitialized in this function [-Wuninitialized]
untitled2.c:50:5: warning: ‘subnetInput’ is used uninitialized in this function [-Wuninitialized]
Compilation finished successfully.

该语句:“编译成功完成。”仅意味着编译器为解决问题而生成了一些“解决方法”的代码。这并不意味着生成的代码是正确的。

每一条“使用未初始化”消息都在告诉您一些未定义的行为。

所以无论代码输出什么都是没有意义的。

建议修复代码，以便它可以干净地编译