这个怎么做？是不是有什么限制

C++

#include <iostream>
using namespace std;
int main()
{
    unsigned int a,b;
    double c;
    cin >> a >> b;
    c = a*b;
    cout << c << endl;
    return 0;
}

C代码

#include <stdio.h>

int main()
{
    unsigned int a,b;
    double c;
    scanf("%u,%u",&a,&b);
    c = a*b;
    printf("%g\n",c);
    return 0;
}

int main()
{
    int A,B;
    scanf("%d%d",&A,&B);
    printf("%d",A*B);
    return 0;
}

#include <stdio.h>
int main()
{
    int a, b;
    scanf("%d%d", &a, &b);
    printf("%d", a * b);
}

#include <stdio.h>
int main() {
   int a,b;
  scanf("%d %d",&a,&b);
  printf("%d",a*b);
  return 0;
}