我只需要一副额外的眼睛来帮助我找出为什么这段代码是segfaulting。
//------------------------Preprocessor Instructions. ------------------------------------
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#define NUMBER 128 //Maxmimum number of items/lines in file.
#define BUFFER 120 //Buffer length (For user input)
#define LENGTH 32 //Maximum length of lines in file.
//------------------------Global stuff. ---------------------------------------------
int iterations=0; //Will count number of times the calculation function is called.
int weight[NUMBER];
int value[NUMBER];
char object[NUMBER][LENGTH];
//------------------------Function Definitions. -----------------------------------------
void printarr();
//------------------------Printarr -- Array printing function. --------------------------
void printarr()
{
int i,j;
printf("\n");
printf("Weight \t Value \t Object \n");
for(i=0;i<4;i++){
printf("%d \t %d \t %s \n", weight[i], value[i], &object[i][0]);
}
}
//------------------------Main. ---------------------------------------------------------
int main(int argc, char **argv)
{
FILE *fp; //File pointer.
char buffer[BUFFER]; //Temporary storage
int result; //sscanf return value.
int capacity; //User input.
int i,j=0; //Loop counters.
//Command Line Argument Parsing: Assigns input value to capacity.
if (argc != 2){
printf("Usage: %s number. Max 1024. \n",argv[0]); //Usage: *program* *num*
return(1);
}
if (1 != sscanf(argv[1],"%d",&capacity)){
printf("Usage: %s number. Max 1024. \n",argv[0]);
return(1);
}
//File reading.
fp=fopen("knapsack.data","r");
if(NULL==fp){
printf("Error opening file. \n");
exit(0);
}
//Write to arrays.
while(NULL != fgets(buffer, BUFFER, fp)){
result=sscanf(buffer, "%d %d %s", &weight[i], &value[i], &object[i][0]);
i++;
}
//Print the arrays.
printarr();
fclose(fp);
}
根据GDB的说法,当它遇到sscanf声明时会出现段错误。但据我所知,我访问这些地点的方式并没有错......显然我错了。任何帮助,将不胜感激。
答案 0 :(得分:-2)
编辑:我是对的,修好这一行:
result=sscanf(buffer, "%d %d %s", &weight[i], &value[i], &object[i][0]);
看起来像这样:
result=sscanf(buffer, "%d %d %s", &weight[i], &value[i], object[i]);
您正在读取整个字符串,因此您需要写入c字符串位置,在本例中为object [i]。另外,init i是最佳实践(尽管如果未初始化,gcc会初始化为零,请自行尝试并查看)。
编辑:忽略downvote,我是正确的但我确实在忘记删除你的第二个索引时出错了,你可以使用object [i]或&amp; object [i] [0]访问ac string 2d数组,两者都是工作。用于访问整个字符串的object [i]看起来比使用&amp; object [i] [0]更清晰。