我有一个问题，我的程序 - 在Windows中运行正常 - 在Linux中给我一个分段错误。我已经搜索了许多其他涉及分段错误的问题，我认为它必须对我做一些事情，而不是正确使用malloc。
该程序应该采用一个数据文件，该文件被假定为一个列表事件，它具有多个任务，每个任务都有一个相关的完成日期所需的天数。例如，我正在测试的数据文件如下所示：
1 15 3
1 27 6
1 36 4
2 15 5
3 18 4
3 26 1
4 15 2
4 26 7
4 27 7
5 16 4
左列是事件编号，中间列是任务编号，右列是所需的天数。以下是我的代码。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char *argv[])
{
// Declare variables to be used
FILE *in;
FILE *out;
char* inName;
char* outName;
int eventNum, taskNum, daysNum;
int amtEvents, totalDays = 0;
int **events;
int **data, dataSize = 0;
int currentEvent = 1;
// Exit program if there are too few arguments entered
if(argc < 2)
{
printf("Too few arguments.");
return 0;
}
// Locate the -input and -output tags to determine
// file names
for(int i=0; i<argc; i++)
{
if(! strcmp(argv[i], "-input"))
{
inName = malloc(strlen(argv[i+1]) * (sizeof(char)));
strcpy(inName, argv[i+1]);
}
if(!strcmp(argv[i], "-output"))
{
outName = malloc(strlen(argv[i+1]) * (sizeof(char)));
strcpy(outName, argv[i+1]);
}
}
if ((in = fopen(inName, "r")) == NULL){
fprintf(stderr, "Input file usage: %s", inName);
return 0;
}
out = fopen(outName, "w");
while (!feof(in)) {
if (fscanf(in, "%d %d %d", &eventNum, &taskNum, &daysNum) != 3)
break;
dataSize++;
}
in = fopen(inName, "r");
// Store the data in the file into a
// dynamically created 2D array
data = malloc((dataSize) * sizeof(int));
while (!feof(in)) {
for(int i=0; i < dataSize+1; i++){
data[i] = malloc(3 * sizeof(int));
if (fscanf(in, "%d %d %d", &eventNum, &taskNum, &daysNum) != 3)
break;
data[i][0] = eventNum;
data[i][1] = taskNum;
data[i][2] = daysNum;
}
}
// Increment amtEvents for each unique event number
amtEvents = 1;
for(int i=0; i<dataSize; i++)
{
while(currentEvent != data[i][0])
{
amtEvents++;
currentEvent++;
}
}
// Create another 2D array to store data about
// each event
events = malloc(amtEvents * sizeof(int));
for(int i=0; i < amtEvents+1; i++)
{
events[i] = malloc(3 * sizeof(int));
for(int j=0; j<3; j++){
events[i][j] = 0;
}
}
for(int i=0; i < dataSize; i++)
{
events[data[i][0]-1][1]++;
if(data[i][2] > events[data[i][0]-1][2])
events[data[i][0]-1][2] = data[i][2];
}
// Header
fprintf(out, "Project completion timetable\n");
fprintf(out, "----------------------------------------\n");
fprintf(out, "Event\tNum of tasks\tMax num.of days\n");
fprintf(out, "-----\t------\t\t--------\n");
for(int i=0; i<amtEvents; i++)
{
fprintf(out, "%d\t %d\t\t %d\n", i+1, events[i][1], events[i][2]);
totalDays += events[i][2];
}
fprintf(out, "----------------------------------------\n");
fprintf(out, "Total number of days to finish the project: %d", totalDays);
free(inName);
free(outName);
free(data);
free(events);
}
我对使用gdb并不是很熟悉，但我通过它运行我的程序，这就是它告诉我的：
Program received signal SIGSEGV, Segmentation fault.
0x0000555555554ead in main ()
好的，谢谢你的帮助。我实施了一些你们建议的改动，现在似乎工作正常。
我认为错误的原因是我在malloc和inName使用outName时不记得要考虑空终结符。
答案 0 :(得分：0)
你遇到了各种各样的问题。我做了一些更正，这段代码似乎对我有用。我刚刚使用valgrind检查来查找您的错误。
一般来说，使用FILE *in = NULL;初始化指针始终是一个很好的策略。
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main(int argc, char *argv[])
{
// Declare variables to be used
FILE *in = NULL;
FILE *out = NULL;
char* inName = NULL;
char* outName = NULL;
int eventNum, taskNum, daysNum;
int amtEvents, totalDays = 0;
int **events;
int **data, dataSize = 0;
int currentEvent = 1;
// Exit program if there are too few arguments entered
if(argc < 2)
{
printf("Too few arguments.");
return 0;
}
// Locate the -input and -output tags to determine
// file names
int i;
for(i=0; i<argc; i++)
{
if(! strcmp(argv[i], "-input"))
{
inName = malloc(strlen(argv[i+1]) * (sizeof(char)));
strcpy(inName, argv[i+1]);
}
if(!strcmp(argv[i], "-output"))
{
outName = malloc(strlen(argv[i+1]) * (sizeof(char)));
strcpy(outName, argv[i+1]);
}
}
if ((in = fopen(inName, "r")) == NULL){
fprintf(stderr, "Input file usage: %s", inName);
return 0;
}
out = fopen(outName, "w");
while (!feof(in)) {
if (fscanf(in, "%d %d %d", &eventNum, &taskNum, &daysNum) != 3)
break;
dataSize++;
}
in = fopen(inName, "r");
// Store the data in the file into a
// dynamically created 2D array
data = malloc((dataSize) * sizeof(int));
while (!feof(in)) {
for(i=0; i < dataSize+1; i++){
data[i] = malloc(3 * sizeof(int));
if (fscanf(in, "%d %d %d", &eventNum, &taskNum, &daysNum) != 3)
break;
data[i][0] = eventNum;
data[i][1] = taskNum;
data[i][2] = daysNum;
}
}
// Increment amtEvents for each unique event number
amtEvents = 1;
for(i=0; i<dataSize; i++)
{
while(currentEvent != data[i][0])
{
amtEvents++;
currentEvent++;
}
}
// Create another 2D array to store data about
// each event
events = malloc(amtEvents * sizeof(int));
for(i=0; i < amtEvents+1; i++)
{
events[i] = malloc(3 * sizeof(int));
int j;
for(j=0; j<3; j++){
events[i][j] = 0;
}
}
for(i=0; i < dataSize; i++)
{
events[data[i][0]-1][1]++;
if(data[i][2] > events[data[i][0]-1][2])
events[data[i][0]-1][2] = data[i][2];
}
// Header
fprintf(out, "Project completion timetable\n");
fprintf(out, "----------------------------------------\n");
fprintf(out, "Event\tNum of tasks\tMax num.of days\n");
fprintf(out, "-----\t------\t\t--------\n");
for(i=0; i<amtEvents; i++)
{
fprintf(out, "%d\t %d\t\t %d\n", i+1, events[i][1], events[i][2]);
totalDays += events[i][2];
}
fprintf(out, "----------------------------------------\n");
fprintf(out, "Total number of days to finish the project: %d", totalDays);
free(inName);
free(outName);
free(data);
free(events);
return 0;
}
** PS：使用此代码我在Centos7中有一个干净的账单 - Codeblocks - GNU GCC。