接受输入后，C程序“卡住" [英] C Program 'stuck' After Accepting Input

问题描述

很抱歉标题的措辞，我想不出一种更好的方式来表达我的问题.在我的代码中，我将n个输入集用于一个我称为时间间隔的结构.如果用户只想输入1个结构，则程序接受输入并打印就好.但是，任何大于1的值都将接受所有输入，但是在最后一个在结构内部存储整数的输入之后，它将变为粘滞"状态，光标将向下移动一行，就好像它在等待输入一样.不管您输入什么，程序都不会进行.我需要了解导致程序停止运行的原因.感谢您提供的所有帮助.

Sorry for the wording of the title, I could not think of a better way to word my question. In my code I am taking n sets of input for a struct I call interval. If the user only wants to enter 1 structure, then the program accepts input and prints just fine. However, anything greater than 1 will accept all the input, but after the last input that stores an integer inside the structure, it will become 'stuck' where the cursor will move down one line as if it is waiting for input. Except no matter what you enter the program doesn't progress at all. I need to understand what is stopping my program from progressing. Thanks for any and all help.

调用takeInput函数时，错误(我假设是)主要存在.

The error (I assume) is in the main when the function takeInput is called.

我在Linux机器上使用gcc进行了编译.下面是代码.

I compiled using gcc on a Linux machine. Below is the Code.

#include <stdio.h>

typedef struct interval{
    int num_left, denum_left;
    int num_right, denum_right;
    int left_state, right_state;
}interval;

interval combine(interval x, interval y);
int combineCheck(interval x, interval y);
int valueCheck(interval x, interval y);
void mergeSort(interval x[], int l, int r);
void merge(interval x[], int l, int m, int r);
interval takeInput();

int main(){
    int response, i;
    char d;
    printf("Enter the number of intervals to input: ");
    scanf("%d", &response);
    interval data[response];

    for(i = 0; i < response; i++){
        data[i] = takeInput();
    }
    printf("%d/%d   %d/%d", data[0].num_left, data[0].denum_left, data[0].num_right, data[0].denum_right);

    mergeSort(data, 0, response-1);

    printf("%d/%d   %d/%d", data[0].num_left, data[0].denum_left, data[0].num_right, data[0].denum_right);
}

interval takeInput(){
    interval temp;
    printf("Enter left numerator: ");
    scanf("%d", &temp.num_left);
    printf("Enter left denominator: ");
    scanf("%d", &temp.denum_left);
    printf("Enter right numerator: ");
    scanf("%d", &temp.num_right);
    printf("Enter right denominator: ");
    scanf("%d", &temp.denum_right);
    printf("\n");

    if(temp.num_left < 0){
        temp.num_left = temp.num_left*-1;
        temp.left_state = -1;}
    else{
        temp.left_state = 0;}

    if(temp.num_right < 0){
        temp.num_right = temp.num_right*-1;
        temp.right_state = -1;}
    else{
        temp.right_state = 0;}
    printf("Testing Shit");
    return temp;
}

int combineCheck(interval x, interval y){
    int left, right;
    left = x.num_right * y.denum_left;          //used to find relationship between 2 fractions
    right = y.num_left * x.denum_right;

    if(left == right && (x.right_state + x.left_state) == 0){
        return 1;
    }
    else if(left > right){
        return 1;
    }
    return 0;
}

interval combine(interval x, interval y){
    int left, right;                        //used to check if one interval is all encompassing
    left = x.num_right * y.denum_right;
    right = x.denum_right * y.num_right;

    interval temp;
    temp.num_left = x.num_left;
    temp.denum_left = x.denum_left;
    temp.left_state; 
    if(left > right){
        temp.num_right = x.num_right;
        temp.denum_right = x.denum_right;
        temp.right_state = x.right_state;
        return temp;
    }
    temp.num_right = y.num_right;
    temp.denum_right = y.denum_right;
    temp.right_state = y.right_state;
    return temp;
}

int valueCheck(interval x, interval y){
    int first, second;                  //used to check values
    first = x.num_left * y.denum_left;
    second = y.num_left * x.denum_left;
    if(first > second){
        return 1;
    }
    return -1;
}

void mergeSort(interval x[], int l, int r){
    if(l < r){
        int m = l + (r-1)/2;

        mergeSort(x, l, m);
        mergeSort(x, m+1, r);
        merge(x, l, m, r);
    }
}

void merge(interval arr[], int l, int m, int r){
    int i, j, k;
    int n1 = m-l +1;
    int n2 = r-m;

    interval L[n1], R[n2];

    for(i = 0; i < n1; i++)
        L[i] = arr[l + i];
    for(j = 0; j < n2; j++)
        R[j] = arr[m + 1 + j];
    j = 0;
    i = 0;
    k = l;
    while(i < n1 && j < n2){
        if(valueCheck(L[i], R[j]) == -1){
            arr[k] = L[i];
        }
        else{
            arr[k] = R[j];
            j++;
        }
    }

    while(i < n1){
        arr[k] = L[i];
        i++;
        k++;
    }

    while(j < n2){
        arr[k] = R[j];
        j++;
        k++;
    }
}

这是输出的样子

推荐答案

合并排序例程中存在一些问题:

You have some problem in your merge sort routine:

k = l;
while(i < n1 && j < n2){
    if(valueCheck(L[i], R[j]) == -1){
        arr[k] = L[i];
    }
    else{
        arr[k] = R[j];
        j++;
    }
}

分配给arr后，您不会增加i.由于我永不改变，因此while循环永远不会终止.在第一个if条件中添加i++，它将起作用.还请参见MondKin提出的观点，这也是您的代码中非常严重的问题.

You're not incrementing i after assigning to arr. Since i is never changing, your while loop never terminates. Add a i++ in that first if condition and it would work. Also see the point made by MondKin, that's also a very serious problem in your code.

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