C++ 错误：“(”标记之前的预期标识符
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C++ error: expected identifier before "(" token
提问by Andrew
int nn1,nn2;
for (int i=1;i<=m;i++) if (A[i]>minim) && (A[i]<maxim) nn1++;
for (int j=1;j<=n;j++) if (B[j]>minim) && (B[j]<maxim) nn2++;
if (nn1>nn2) cout<<"1";
if (nn1<nn2) cout<<"2";
if (nn1=nn2) cout<<"0";
return 0;
}
can anybody give me a suggestion please why the compiler shows the error?
任何人都可以给我一个建议，为什么编译器会显示错误？
回答by Vlad from Moscow
In these if statements there are absent external parentheses
在这些 if 语句中没有外括号
for (int i=1;i<=m;i++) if (A[i]>minim) && (A[i]<maxim) nn1++;
for (int j=1;j<=n;j++) if (B[j]>minim) && (B[j]<maxim) nn2++;
I think that there should be
我认为应该有
for (int i=1;i<=m;i++) if ( (A[i]>minim) && (A[i]<maxim) ) nn1++;
for (int j=1;j<=n;j++) if ( (B[j]>minim) && (B[j]<maxim) ) nn2++;
And the loops look suspeciously. Take into account that array indices start from 0. So for example if you have an array of size Nthen the valid range of indices is [0, N-1]
循环看起来很可疑。考虑到数组索引从 0 开始。例如，如果你有一个大小的数组，N那么索引的有效范围是[0, N-1]
And you forgot to initialize nn1and nn2.
而你忘了初始化nn1和nn2。
It seems that you mean the following
看来你的意思是以下
int nn1 = 0, nn2 = 0;
for ( int i = 0; i < m; i++ )
{
if ( ( A[i] > minim ) && ( A[i] < maxim ) ) nn1++;
}
for ( int i = 0; i < n; i++ )
{
if ( ( B[i] > minim ) && ( B[i] < maxim ) ) nn2++;
}
if ( nn1 > nn2 ) cout << "1";
else if ( nn1 < nn2 ) cout << "2";
else cout << "0";
回答by animageofmine
Fix the brackets in if condition. Something like if (condition1 && condition2). I also suggest using curly brackets for every branch condition.
在 if 条件下固定括号。类似于 if (condition1 && condition2)。我还建议对每个分支条件使用大括号。
for (int i=1;i<=m;i++) {
if ((A[i]>minim) && (A[i]<maxim)) {
nn1++;
}
}
for (int j=1;j<=n;j++) {
if ((B[j]>minim) && (B[j]<maxim)) {
nn2++;
}
}
回答by Hashira
In C++,there should be a complete "()" after the "if" and what in "()" is the condition. So,the code you showed is if(A[i]>minim) && (A[i]minim) && (A[i]
在C++中，“if”后面应该有一个完整的“()”，“()”中的什么是条件。所以，你展示的代码是 if(A[i]>minim) && (A[i]minim) && (A[i]
回答by Ayushi Jha
Take care of paranthesis when dealing with ifs:
处理时注意括号ifs：
if ( (B[j]>minim) && (B[j]<maxim) )
| |
V V
Add these
So, your code should be:
所以，你的代码应该是：
int nn1,nn2;
for (int i=1;i<=m;i++) if ( (A[i]>minim) && (A[i]<maxim) ) nn1++;
for (int j=1;j<=n;j++) if ( (B[j]>minim) && (B[j]<maxim) ) nn2++;
if (nn1>nn2) cout<<"1";
if (nn1<nn2) cout<<"2";
if (nn1=nn2) cout<<"0";
return 0;
}
回答by Quentin
Missing parentheses around the whole condition :
整个条件周围缺少括号：
for (int i=1;i<=m;i++) if((A[i]>minim) && (A[i]<maxim)) nn1++;
// ^ ^
回答by Sourav Kanta
You forgot the ( ) in if statement.Try this :
你忘记了 if 语句中的 ()。试试这个：
int nn1,nn2;
for (int i=1;i<=m;i++) if ((A[i]>minim) && (A[i]<maxim)) nn1++; //note extra ()
for (int j=1;j<=n;j++) if ((B[j]>minim) && (B[j]<maxim)) nn2++; //note extra ()
if (nn1>nn2) cout<<"1";
if (nn1<nn2) cout<<"2";
if (nn1=nn2) cout<<"0";
return 0;
}
