求救这是什么原因，我比较菜
#include<iostream.h>
void man
{ char str[];
float b,c;
cout<<"请输入";
gets(str);
if(b<0)a=b;
{ i=1;
while(a[i]=='\0')
cout<<a[i];i++;

}
else cout<<b;
cout <<endl;}

includes, or <iostream> instead of the deprecated header <iostream.h>. To disable this warning use -Wno-deprecated.
09.cpp:3: error: invalid function declaration
09.cpp:14:16: warning: no newline at end of file
编译结束但存在 1 错误 和 2 警告

[解决办法]

C/C++ code

void main()  //少了参数括号{}