Question

基本上我正在尝试打印类似 “ 1 2 3”

但是，当我在终端上运行它时，它却给出了段错误，而没有任何解释...

#include <stdio.h>
#include <string.h>

int main() {
    int width = 4;
    char complete_row[width * 3 * 2];
    char one[3], two[3], three[3], space[1];
            strcpy(space, " ");
            strcpy(complete_row, "");
            int count = 0;
            //make sure single line of color is replicated as much as width
            while (count < width) {
                strcpy(one, "1");
                strcat(one, space);
                strcpy(two, "2");
                strcat(two, space);
                strcpy(three, "3");
                strcat(complete_row, one);
                strcat(complete_row, two);
                strcat(complete_row, three);
            }
            //print that twice in the output file
            printf("%s", complete_row);
            printf("%s", complete_row);
    return 0; 
}

Answer 1

您的代码中至少存在两个问题：

while循环永远不会停止，因为您不会在循环中递增count。因此，您一遍又一遍地将字符串连接到complete_row上，最终导致缓冲区溢出，从而导致未定义的行为（可能是段错误）
char space[1]声明了一个可以只容纳一个字符的数组，但是对于" "，由于NUL字符串终止符，您需要两个字符。超出范围访问数组会导致未定义的行为（可能是段错误）。

正确的代码，请参见注释（未经测试，可能会有更多问题）

int main() {
    int width = 4;
    char complete_row[width * 3 * 2];
    char one[3], two[3], three[3], space[2];  // space[2]
            strcpy(space, " ");
            strcpy(complete_row, "");
            int count = 0;
            //make sure single line of color is replicated as much as width
            while (count < width) {
                strcpy(one, "1");
                strcat(one, space);
                strcpy(two, "2");
                strcat(two, space);
                strcpy(three, "3");
                strcat(complete_row, one);
                strcat(complete_row, two);
                strcat(complete_row, three);
                count++;    // increment count
            }
            //print that twice in the output file
            printf("%s", complete_row);
            printf("%s", complete_row);
    return 0; 
}

Answer 2

您的代码中有两个问题
1.由于您的 count 变量。您不会递增count变量，因此count始终为0，而循环永远不会结束或无限。
2.空间数组的大小不够。

对于您期望的结果，您在编写连接代码时也不必在此处应用循环。因此，删除循环将起作用。粘贴您的工作代码。

#include <stdio.h>
#include <string.h>

int main() {
int width = 4;
char complete_row[width * 3 * 2*2];
char one[3], two[3], three[3], space[1];
        strcpy(space, " ");
        strcpy(complete_row, "");
        int count = 0;
        //make sure single line of color is replicated as much as width

            strcpy(one, "1");
            strcat(one, space);
            strcpy(two, "2");
            strcat(two, space);
            strcpy(three, "3");
            strcat(complete_row, one);
            strcat(complete_row, two);
            strcat(complete_row, three);

        //print that twice in the output file
        printf("%s", complete_row);

return 0;

}

C：为什么会出现细分错误？

2 个答案: