[英]Error Segmentation fault (core dumped)
I am doing some exercises for my university course on C and I have the following code which exits with error Segmentation fault (core dumped) after the user has input the choice (1 or 2). 我正在大学的C语言课程中做一些练习,并且我有以下代码,在用户输入选择(1或2)后,该错误退出并出现错误Segmentation Fault(core dumped)。 I don't know if it's an issue that I am using ubuntu 16.04 and I am compiling my source code files with make command.
我不知道这是我正在使用ubuntu 16.04还是使用make命令编译源代码文件的问题。 Oh and please don't recommend to use the built-in c function strcpy because this exercise is supposed to "teach us' how to make our own string copy.
哦,并且不建议您使用内置的c函数strcpy,因为本练习旨在“教我们”如何制作自己的字符串副本。
So what am I doing wrong? 那我在做什么错?
#include <stdio.h>
#define SIZE 1000
char mystrcpy(char *dest,char *src);
main(){
char str1[SIZE];
char str2[SIZE];
char str3[SIZE];
int choice;
printf("Give first string: ");
gets(str1);
printf("Give second string: ");
gets(str2);
printf("Choose one of two strings (1 h 2): ");
scanf("%d",&choice);
if (choice==1)
mystrcpy(str3,str1);
else (choice==2)
mystrcpy(str3,str2);
printf("\nFirst string is %s\n",str1);
printf("\Second string is %s\n",str2);
printf("\nThrid string is %s\n",str3);
}
char mystrcpy(char *dest,char *src){
int i;
while(1)
{
dest[i] = src[i];
if (src[i] == '\0')
break;
i++;
}
return dest;
}
i
is never initialized. i
从来没有初始化。 (need 30 characters....) (需要30个字符。...)
You are not initializing i
, so it starts at an indeterminate value, hence the segfault. 您不是在初始化
i
,所以它以不确定的值开始,因此存在段错误。
Notice that enabling the warnings would have shown this problem immediately in this simple case; 注意,在这种简单情况下,启用警告将立即显示此问题。 in more complicated scenarios using a debugger would have shown that the value of
i
at the moment of crash would have been completely nonsensical. 在更复杂的情况下,使用调试器将表明崩溃时
i
的值完全是荒谬的。
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