致命错误：iostream：使用 GCC 编译 C 程序时没有此类文件或目录

Question

为什么我在编译以下多线程归并排序 C 程序时，会收到此错误：

 ap@sharifvm:~/forTHE04a$ gcc -g -Wall -o mer mer.c -lpthread
mer.c:4:20: fatal error: iostream: No such file or directory
 #include <iostream>
                    ^
compilation terminated.
ap@sharifvm:~/forTHE04a$ gcc -g -Wall -o mer mer.c -lpthread
mer.c:4:22: fatal error: iostream.h: No such file or directory
 #include <iostream.h>
                      ^
compilation terminated.

我的程序：

 #include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <iostream>
using namespace std;

#define N 2  /* # of thread */

int a[] = {10, 9, 8, 7, 6, 5, 4, 3, 2, 1};  /* target array */

/* structure for array index
 * used to keep low/high end of sub arrays
 */
typedef struct Arr {
    int low;
    int high;
} ArrayIndex;

void merge(int low, int high)
{
        int mid = (low+high)/2;
        int left = low;
        int right = mid+1;

        int b[high-low+1];
        int i, cur = 0;

        while(left <= mid && right <= high) {
                if (a[left] > a[right])
                        b[cur++] = a[right++];
                else
                        b[cur++] = a[right++];
        }

        while(left <= mid) b[cur++] = a[left++];
        while(right <= high) b[cur++] = a[left++];
        for (i = 0; i < (high-low+1) ; i++) a[low+i] = b[i];
}

void * mergesort(void *a)
{
        ArrayIndex *pa = (ArrayIndex *)a;
        int mid = (pa->low + pa->high)/2;

        ArrayIndex aIndex[N];
        pthread_t thread[N];

        aIndex[0].low = pa->low;
        aIndex[0].high = mid;

        aIndex[1].low = mid+1;
        aIndex[1].high = pa->high;

        if (pa->low >= pa->high) return 0;

        int i;
        for(i = 0; i < N; i++) pthread_create(&thread[i], NULL, mergesort, &aIndex[i]);
        for(i = 0; i < N; i++) pthread_join(thread[i], NULL);

        merge(pa->low, pa->high);

        //pthread_exit(NULL);
        return 0;
}

int main()
{
        ArrayIndex ai;
        ai.low = 0;
        ai.high = sizeof(a)/sizeof(a[0])-1;
        pthread_t thread;

        pthread_create(&thread, NULL, mergesort, &ai);
        pthread_join(thread, NULL);

        int i;
        for (i = 0; i < 10; i++) printf ("%d ", a[i]);
        cout << endl;

        return 0;
}

原文由 Ebrahim Ghasemi 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

<iostream> 和 <iostream.h> 都不是标准的 C 头文件。您的代码是 C++，其中 <iostream> 是一个有效的标头。对 C++ 代码使用 C++ 编译器，例如 clang++ 或 g++ （以及 .cpp 文件扩展名）。

或者，该程序主要使用 C 中可用的构造。将整个程序转换为使用 C 编译器进行编译很容易。 Simply remove #include <iostream> and using namespace std; , and replace cout << endl; with putchar('\n'); … I advise compiling using C99, C11 or C18 (eg. gcc -std=c99 ， clang -std=c18 等）

原文由 autistic 发布，翻译遵循 CC BY-SA 4.0 许可协议