我编写了一个包含M * N个元素的程序，其中用户输入了变量M和N.程序在M x N表中打印元素，并为每个元素分配随机值。当我尝试编译程序时，两个错误不断弹出。第一个说第12行有一个函数“PopulateRandom”的隐式声明。第二个消息表示在第25行的“int”之前有一个缺少的表达式。
#include <stdio.h>
#include <stdlib.h>
// Prints elements of array in a M x N table
int PrintArray2D(int M, int N){
int array[M*N], row, column, i;
while(row <= M && column <= N){
for(row = 0; row <= M; row++){
for(column = 0; column <= N; column++){
array[i] = PopulateRandom(array[M * N]);
printf("%d", array[i]);
if(column == 4){
break;
}
}
column = 0;
printf("\n");
}
}
return array[i];
}
//Assigns elements of the array "array" random values
int PopulateRandom(int array[int M * int N]){
int i;
while(i = 0; i < M*N; i++){
array[i] = rand() % (M*N);
}
return array[i];
}
int main(void){
int option, M, N;
printf("If you would like to search ann array, enter 1 \n: ");
printf("If you would like to exit, enter 0 \n: ");
scanf("%d", &option);
while(option != 0){
switch(option){
case 1: if(option == 1){
printf("Enter two numbers M and N: ");
scanf("%d %d", &M, &N);
PrintArray2D(M, N);
}
case 0: if(option == 0){
break;
}
}
printf("If you would like to search ann array, enter 1 \n: ");
printf("If you would like to exit, enter 0 \n: ");
scanf("%d", &option);
}
}
答案 0 :(得分：0)
编译器抱怨函数USE [DATABASENAME]
IF EXISTS (
SELECT * FROM sys.objects
WHERE object_id = OBJECT_ID(N'[DBO].[TABLENAME] ')
AND type in (N'U')
)
DROP TABLE [DBO].[TABLENAME]
SELECT *
into [DBO].[TABLENAME]
FROM OPENQUERY(QUICKBOOKS, 'SELECT * FROM Invoice')
的隐式声明，因为您在之前声明/定义它之前调用它。在PopulateRandom中调用之前，只需定义PopulateRandom即可。
对此，您可能会发现this很有趣。
第二个问题可能是由这行代码引起的：
PrintArray2D如果要连接更多条件，则应使用逻辑和（＆amp;＆amp;）或/和逻辑或（||）。
你使用while循环的方式使得它不正确。 while循环不是for循环，语法不同。
for-loop语法：
while(i = 0; i < M*N; i++)
while循环语法：
for (init; condition; increment)
我能看到的其他问题是：
while (cond1 && cond2 || cond3)
，以防万一。
此外，你总是必须打破案件。你没有打破default。 case 1的一般语法：
switch statement在switch (x)
{
case 1 :
break;
case n :
break;
default:
break;
}
：
PopulateRandom
应该是
int array[int M * int N]
或
int array []
答案 1 :(得分：0)
在此功能中
int PrintArray2D(int M, int N){
int array[M*N], row, column, i;
while(row <= M && column <= N){
for(row = 0; row <= M; row++){
for(column = 0; column <= N; column++){
array[i] = PopulateRandom(array[M * N]);
printf("%d", array[i]);
if(column == 4){
break;
}
}
column = 0;
printf("\n");
}
}
return array[i];
}
变量row，column和i未初始化
int array[M*N], row, column, i;
^^^^^^^^^^^^^^
然而，因此它们在循环中相应地使用
while(row <= M && column <= N){
并在此表达式语句中
array[i] = PopulateRandom(array[M * N]);
同样在此语句中，在函数调用后缀表达式中使用了名称PopulateRandom，但尚未声明。此外，在此表达式array[M * N]中，尝试访问数组之外的内存。
目前尚不清楚这个神奇的数字4在本声明中的含义
if(column == 4){
^^^
还完全不清楚这个带有未初始化变量i
return array[i];
此功能声明
int PopulateRandom(int array[int M * int N]){
int i;
while(i = 0; i < M*N; i++){
array[i] = rand() % (M*N);
}
return array[i];
}
无效。你可以写例如
int PopulateRandom(int M, int N, int array[M * N]){
//...
同样不清楚return语句的目的
return array[i];
尝试返回数组中不存在的元素。
在标签case 1:的switch语句中，您应附加break语句。
可以通过以下方式编写循环
do
{
printf("If you would like to search an array, enter 1 \n: ");
// ^^^
printf("If you would like to exit, enter 0 \n: ");
option = 0;
scanf("%d", &option);
switch( option )
{
case 1:
{
printf("Enter two numbers M and N: ");
scanf("%d %d", &M, &N);
int a[M][N];
PrintArray2D( M, N, a );
break;
}
}
} while ( option != 0 );
函数本身可以按照以下演示程序中的说明进行编写
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
void PopulateRandom( int m, int n, int a[static const m * n] )
{
const int N = m * n;
srand( ( unsigned int )time( NULL ) );
for( int i = 0; i < N; i++ ) a[i] = rand() % N;
}
void PrintArray2D( int m, int n, int a[static const m * n] )
{
PopulateRandom( m, n, a );
for ( int i = 0; i < m; i++ )
{
for ( int j = 0; j < n; j++ )
{
printf( "%3d ", a[i * n + j] );
}
printf( "\n" );
}
}
int main(void)
{
int m = 2;
int n = 3;
int a[m * n];
PrintArray2D( m, n, a );
return 0;
}
程序输出可能看起来像
1 2 2
3 5 0
答案 2 :(得分：0)
这是我在这个论坛上的第一个答案。对我的解释或更正要温和。祝你今天愉快 ！ （只是评论编程更简单）
#include <stdio.h>
#include <stdlib.h>
/*
-You need to use prototype or just set function "int PopulateRandom" before "int PrintArray2D"
-Try to change your way to process at this application, it's really so complicated.
-Try to use debug for understand what is going on your program.
*/
int PrintArray2D(int M, int N){
int array[M*N], row, column, i; // Use "static int" for row, column and i for auto init at 0, or do it manually.
while(row <= M && column <= N){ // Like i have said in top, you use variable but they're not initialized
for(row = 0; row <= M; row++){
for(column = 0; column <= N; column++){
array[i] = PopulateRandom(array[M * N]); // use directly "array[i] = (int) rand();" for change with random value
printf("%d", array[i]); // you can directly print a random value, you save value, but when you leave this function, your array is destroy.
if(column == 4){
break;
}
}
column = 0;
printf("\n");
}
}
return array[i]; // return is useless for your usage, becaus you don't catch return value in your main. (void PrintArray2D if no return)
}
/*
-Your function need other params : int array[], int M, int N (don't forget to send M and N when you call this function)
-You need to change your algo, because this function take M and N for change just ONE element of this array.
-This function is useless in this context, check comment in "PrintArray2D" for more informations
*/
int PopulateRandom(int array[int M * int N]){
int i;
while(i = 0; i < M*N; i++){ // It's a FOR and not WHILE
array[i] = rand() % (M*N);
}
return array[i];
}
/*
-Duplicate code isn't good, you can use printf and scanf just one time, just after your while, and set option = 1 before.
-Donc use case, but just an if, because your condition in your while check the value.
*/
int main(void){
int option, M, N;
printf("If you would like to search ann array, enter 1 \n: ");
printf("If you would like to exit, enter 0 \n: ");
scanf("%d", &option);
while(option != 0){
switch(option){
case 1: if(option == 1){
printf("Enter two numbers M and N: ");
scanf("%d %d", &M, &N);
PrintArray2D(M, N);
}
case 0: if(option == 0){
break;
}
}
printf("If you would like to search ann array, enter 1 \n: ");
printf("If you would like to exit, enter 0 \n: ");
scanf("%d", &option);
}
}