一个C 的 函数指针有关问题

一个C 的 函数指针问题
#include<stdio.h>
#include<stdlib.h>
float main(){
float i=15,j=25,k=50;
float max(float a,float b,float c);
float min(float a,float b,float c);
float average(float a,float b,float c);

float (*f)(float,float,float);
f=max;printf("max=%d\n",f(i,j,k));

f=min;printf("min=%d\n",f(i,j,k));

f=average;printf("average=%d\n",f(i,j,k));

system("pause");
}
float max(float a,float b,float c){
float m;
m=a>b?a:b;
m=m>c?m:c;
return m;
}

float min(float a,float b,float c){
float m;
m=a<b?a:b;
m=m<c?m:c;
return m;
}

float average(float a,float b,float c){
float m;
m=(a+b+c)/3;
return m;
}


怎执行的结果是 全 0？？

[解决办法]
2个问题 
1 int main
2 打印float要用printf("%f",...);