新知识点：输出%要打%%，不然没有

C++ 代码

#include <cstdio> 
#include <cmath>
#include <iostream>

using namespace std;

int main()
{
    int x[6] = {0, 15, 12, 10, 7, 4};
    double a;
    cin >> a;

    int i;
    if(a <= 400) i = 1;
    else if(a <= 800) i = 2;
    else if(a <= 1200) i = 3;
    else if(a <= 2000) i = 4;
    else i = 5;

    printf("Novo salario: %.2f\n",a*(1+x[i]/100.0));
    printf("Reajuste ganho: %.2f\n",a*x[i]/100);
    printf("Em percentual: %d %%",x[i]);

    return 0;
}