Question

分段错误发生在函数un（）中，它返回两个数组的并集但这里是完整的代码以防万一。我已经尝试在un（）中添加一些print语句但它仍然显示Segmentation fault而没有别的。

我正在使用GCC。

#include <stdio.h>
#include <stdlib.h>

void input_set(int* set, int size) {
    int i;
    for(i = 0; i < size; i++) {
        scanf("%d", set+i);
        if(i != 0 && set[i] == set[i-1]) {
            printf("A set cannot have repeated values. Enter again!\n");
            i--;
        }
    }
}

void display_set(int *set, int size) {
    int i;

    printf("{ ");
    for(i = 0; i < size-1; i++)
        printf("%d, ", set[i]);
    printf("%d }\n\n", set[size-1]);
}

int* difference(int *setA, int sizeA, int *setB, int sizeB, int *size) {
    int *setC = malloc(sizeof(int) * (sizeA < sizeB) ? sizeA : sizeB);
    int i, j, present = 0;
    *size = 0;

    for(i = 0; i < sizeA; i++) {
        for(j = 0; j < sizeB; j++)
            if(setA[i] == setB[j]) {
                present = 1;
                break;
            }
        if(!present)
            setC[(*size)++] = setA[i];
        present = 0;
    }

    return setC;
}

int* intersection(int *setA, int sizeA, int *setB, int sizeB, int *size) {
    int size1;
    int *set1 = difference(setA, sizeA, setB, sizeB, &size1);
    int *set2 = difference(setA, sizeA, set1, size1, size);

    return set2;
}

int* un(int *setA, int sizeA, int *setB, int sizeB, int *size) {
    int size1, size2, size3;
    int i;
    int *s1 = difference(setA, sizeA, setB, sizeB, &size1);
    int *s2 = intersection(setA, sizeA, setB, sizeB, &size2);
    int *s3 = difference(setB, sizeB, setA, sizeA, &size3);
    int *set = malloc(sizeof(int) * (size1 + size2 + size3));
    *size = 0;

    for(i = 0; i < size1; i++)
        set[*(size)++] = s1[i];
    for(i = 0; i < size2; i++)
        set[*(size)++] = s2[i];
    for(i = 0; i < size3; i++)
        set[*(size)++] = s3[i];

    return set;
}

void main() {
    int *setA, *setB, *setC;
    int sizeA, sizeB, size;

    printf("Enter the size of set A and B : ");
    scanf("%d %d", &sizeA, &sizeB);

    setA = malloc(sizeof(int)*sizeA);
    setB = malloc(sizeof(int)*sizeB);

    printf("Enter the values in set A :\n");
    input_set(setA, sizeA);

    printf("Enter the values in set B :\n");
    input_set(setB, sizeB);

    printf("A union B = ");
    setC = un(setA, sizeA, setB, sizeB, &size);
    display_set(setC, size);

    printf("A intersection B = ");
    setC = intersection(setA, sizeA, setB, sizeB, &size);
    display_set(setC, size);

    printf("A - B = ");
    setC = difference(setA, sizeA, setB, sizeB, &size);
    display_set(setC, size);

    printf("B - A = ");
    setC = difference(setB, sizeB, setA, sizeA, &size);
    display_set(setC, size);
}

我们非常感谢您对代码质量的任何帮助甚至评论。

Answer 1

toto.c:25:54: warning: operator '?:' has lower precedence than '*'; '*' will be evaluated first [-Wparentheses]
    int *setC = malloc(sizeof(int) * (sizeA < sizeB) ? sizeA : sizeB);
                       ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^

我认为使用更好的编译器进行编译并激活警告会给你一些好的指示......

找不到分段故障发生的位置

1 个答案: