Question

这个代码在我的电脑上工作得很好，而我用codeblocks 10.05编译它。代码不会给出任何错误或警告！但是在将它提交给在线评判编码社区时，他们会回复我一个编译错误！这是我的代码：

#include<stdio.h>
#include<stdlib.h>
int main()
{
    int j=1;
    while(j=1){
        int x,y,i,j,num,count=0,p,k;
        for(;;){
            printf("enter two integers. they must not be equal and must be between 1 and 100000\n");
            scanf("%d%d",&i,&j);
            if(i>=1 && i<100000 && j>=1 && j<100000 && i!=j){
                break;
            }
            else{
                printf("try the whole process again\n");
            }
        }
        if(i>j){
            x=i;
            y=j;
        }
        else{
            x=j;
            y=i;
        }//making x always greater than y
        int *cyclelength=(int *)malloc(5000*sizeof(int));
        if (NULL==cyclelength){
            printf("process aborted");
            return 0;
        }
        else{
            /*solution part for the range of number. and solution for each number  put into cyclelength.*/
            num=y;
            while(num<=x){
                p=1;
                k=num;
                while(k!=1){
                    if(k%2==0)
                        k=k/2;
                    else
                        k=3*k+1;
                    p+=1;
                    }
                cyclelength[count]=p;
                num+=1;
                count+=1;
            }
            int c=0;
            int max=cyclelength[c];
            for(c=0;c<x-y-1;c+=1){
                if(max<cyclelength[c+1]){
                    max=cyclelength[c+1];
                }
            }
            free(cyclelength);
            cyclelength = NULL;
            printf("%d,%d,%d\n",i,j,max);
        }
    }
}

当我尝试在 ANSI C 4.1.2 - GNU C编译器下的在线社区中提交它时，选项：-lm -lcrypt -O2 -pipe -ansi -DONLINE_JUDGE 这种格式。他们发给我一个编译错误信息！

Our compiler was not able to properly proccess your submitted code. This is the error returned:
code.c: In function 'main':
code.c:25:10: error: expected expression before '/' token
code.c:27:19: error: 'cyclelength' undeclared (first use in this function)
code.c:27:19: note: each undeclared identifier is reported only once for each function it appears in
code.c:10:18: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result

为什么我会这样？我的错在哪里？编码格式不匹配吗？我是初学者！

Answer 1

使用-ansi选项，错误是ANSI合规性失败：

}//making x always greater than y

应该是

} /* making x always greater than y */

在第26行;你不能在这里宣布循环长度;它需要位于函数的顶部（第5行）

int main()
{
    int *cyclelength;
...
    cyclelength=(int *)malloc(5000*sizeof(int));

scanf问题是一个警告，因为不检查scanf的返回值会假定它已成功;所以你应该做点什么：

do {
    printf("enter two integers. they must not be equal and must be between 1 and 100000\n");
    number_read = scanf("%d%d", &i, &j);
    if (number_read < 0) /* read failed, e.g. user entered ctrl-d */
        return 0;
    } while (number_read != 2);

当然，您需要在函数顶部声明number_read

Answer 2

您的代码不是ANSI C - 您无法像在C ++和C99中那样在块的中间定义变量。将cyclelength，c，max等的声明移到各自块的顶部。对于严格的ANSI，您还需要使用仅限C的注释，即将// comment更改为/* comment */。

在我的编译器中完全正常工作，但在将其提交给在线社区时会出现编译错误

2 个答案: