Question

注:这是一个家庭工作问题。

Use FOR construction to fill 2D board with values that were given by user. The program asks for board size n, m and then it asks for each board value.

My try

#include <stdio.h>
int main(){
    printf("Enter the number of columns");
    int i = scanf("%d",&i);
    printf("Enter the number of rows");
    int y = scanf("%d",&y);

    int r[i][y];
    int a;
    int b;
    for (a=0; a<i; a++){
        for(b=0; b<y; b++){
            int r[a][b] = scanf("%d",&a,&b); //bug
        }
    }
}

<代码>Bug: c:13个变型物体不得入选

http://www.un.org。

#include <stdio.h>

int main(){

    printf("Enter the number of columns");
    int i; 
    scanf("%d", &i);
    printf("Enter the number of rows");
    int y; 
    scanf("%d", &y);

    int r[i][y];
    int a;
    int b;

        for (a=0; a<i; a++){
            for (b=0; b<y; b++){
    scanf("%d",&r[a][b]);
        }
    }
}

Answer 1

>>scanf 处理正在读到的变量,将项目编号改为。该数值不折成美元。

替换

int i = scanf("%d",&i);
int y = scanf("%d",&y);

页: 1

scanf("%d",&i);
scanf("%d",&y);

以及

int r[a][b] = scanf("%d",&a,&b);

页: 1

scanf("%d",&r[a][b]);

http://www.un.org。

You are using variable length array (VLA) in your program:

int r[i][y];

as i 以及 y are not constants 以及 are variables. VLA are a C99 st以及ard feature.

Answer 2

你们必须积极分配2D阵列,否则就不知道它的规模。

替换

int r[i][y];

iii

int *r = malloc(i*y*sizeof(int));

增加:

free(r);

* 以及SCANF错误,人们已经在这里回答。

Answer 3

首先,<代码>scanf的回报值页: 1

第二,C无法通过使用变量创建阵列。你们首先必须积极分配一个阵列。在第一阵列的每一条目中,你必须另设一个阵列。

Don!

Answer 4

The use of scanf(%d, &var) is incorrect.
scanf reads from console an integer (this type is specified by its first paramenter %d) and stores it in the second parameter.
This second parameter must be a pointer, so an & is needed when your variable is not a pointer yet.

因此,你应该以这种方式纠正你的法典:

int i;    
scanf("%d",&i);

int y;
scanf("%d", &y);

和for 住宿

scanf("%d", &r[a][b]);

Answer 5

由于直线缓冲,没有打印电文。

If you add to your strings (to start a new line), it might do what you expect:

printf("Enter the number of columns
");

或者,如果你真的希望用户在同一线路上进行分类,那么你需要人工冲动缓冲:

printf("Enter the number of columns");
fflush (stdout);

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