C语言斜率计算

#include <stdio.h>
#include <stdlib.h>
int main()
{
 //坐标 
 int x1,x2,y1,y2;
 //斜率未必是整数 
 float k;

 printf("please input x1: ");
 scanf("%d",&x1);
 printf("please input y1: ");
 scanf("%d",&y1);
 printf("please input x2: ");
 scanf("%d",&x2);
 printf("please input y2: ");
 scanf("%d",&y2);

 //斜率不存在 
 if(x1-x2==0){
  k=0;
 }

 else{
 //强制类型转化 
   k=(float)(y1-y2)/(x1-x2);
 }

 //控制输出 
 printf("The slope is %5.1f",k);

 system("pause");
 return 0;
 
}