小编Kni*_*nug的帖子

我正在尝试将一些字符串写入文件.编译时没有任何警告,但是当我运行a.out时会出现段错误.但它会创建目标文件.我是C的新手,所以我为我的格式和其他缺点道歉.这是我的代码:

#include<stdio.h>

int main (void)
{
    FILE *fp_out;

    char str1[]="four score and seven years ago our";
    char str2[]="fathers broughy forth on this continent,";
    char str3[]="a new nation, concieved in Liberty and dedicated";
    char str4[]="to the proposition that all men are created equal.";

    fp_out=fopen("my_file", "w");

    if(fp_out!=NULL)
    {
        fprintf(fp_out,"%s\n", str1[100]);
        fprintf(fp_out,"%s\n", str2[100]);
        fprintf(fp_out,"%s\n", str3[100]);
        fprintf(fp_out,"%s\n", str4[100]);
        fclose(fp_out);
    }
    else
        printf("The file \"my_file\" couldn't be opened\n");

    return 0;
}

我刚开始学习C,在一本书的项目中它给了我这段代码:

float fahrenheitFromcelcius (float celcius){
   float fahrenheit = celcius *1.8 +32.0;
   printf("%f celcius is %f fahrenheit\n", celcius , fahrenheit);
   return fahrenheit;
}

为什么我需要返回华氏度.我以为你回来检查一切是否正常或停止功能

到目前为止,我在堆栈溢出时发现了这个,但这只打印出当前目录而不是子目录.提前致谢!

DIR *dir;
struct dirent *ent;

if ((dir = opendir ("c:\\src\\")) != NULL) {
    /* print all the files and directories within directory */
    while ((ent = readdir (dir)) != NULL) {
        printf ("%s\n", ent->d_name);
    }
    closedir (dir);
} else {
    /* could not open directory */
    perror ("");
    return EXIT_FAILURE;
}

我这里有一个程序,它总是将数字的数字相加,直到我得到一个数字.例如,给定num = 38,过程如下:3 + 8 = 11,1 + 1 = 2.由于2只有一位数,所以返回它.

问题是,返回main的值是垃圾,但是在从函数addDigits()返回值之前,它是正确的值.谁能在这看到我的错误？这让我疯狂.提前谢谢了.

#include <iostream>
#include <vector>
#include <stdio.h>

using namespace std;


int addDigits(int num)
{
    vector <int> nums;

    if (num <10)
    {
        return num;
    }

    int rem, temp = 0;

    while (num > 9)
    {
        temp = num /10;
        rem = num %10;
        nums.push_back(rem);
        num = temp;
    }

    nums.push_back(num);

    int total = nums[0];
    for (int i = 1;  i < nums.size(); i++)
    {
        total += nums[i];
    }

    cout<<"total :"<<total<<endl;



    if …

我必须为这段代码绘制进程树：

int main ()
{
    int i;
    for(i = 0; i < 3; i++)
        if(fork() > 0) 
            fork();
    return 0;
}