求指导，c语言，如题

变成好几次咯，这个没有正确答案求知道就知道就知道求知道。如题谢谢

#include<stdio.h>
#include<math.h>
int main(){

    float a=0.0,b=0.0,c=0.0,s=0.0,area=0.0;
    printf("Input a,b,c:\n");
    scanf("%f,%f,%f",&a,&b,&c);
    s=(a+b+c)/2.0;
    area=sqrt(s*(s-a)*(s-b)*(s-c));
    printf("area=%.2f",area);
    return 0;
}

//第二题：
#include<stdio.h>
int main()
{
    int a, b;
    scanf_s("%d,%d", &a, &b);
    if (a > b){
        printf("max = %d\n", a);}
  else{
        printf("max = %d\n", b);}
    return 0;
}

#include<stdio.h>
#include<math.h>
int main()
{
    float a, b, c, area,s;      //引入变量
    scanf_s("%f,%f,%f", &a, &b, &c);   //按要求输入相关值
    s = (a + b + c) / 2;   //算出s
    area = sqrt(s * (s - a) * (s - b) * (s - c));  //根据公式算面积
    printf("area = %.2f\n", area);    //输出结果
    return 0;
}


//第二题
#include<stdio.h>
int main()
{
    int a, b;
    scanf_s("%d,%d", &a, &b);
    if (a > b)
        printf("max = %d\n", a);
    if (a < b)
        printf("max = %d\n", b);
    return 0;
}