#include "stdafx.h"
#include<stdio.h>
int main(void)
{
    float length, width, c;
    printf("Enter the length of the rectangle: \n");
    while(scanf("%f",&length) )
    {
        printf("Length = %0.2f:\n", length);
        printf("Enter its width: \n");
        if(scanf("%f", &width) != 1)
            break;
        printf("width = %0.2f:\n", width);
        c = length * width;
        printf("Enter the length of 1 the rectangle:\n" );
    }
    printf("Done.\n");
    getchar();
    return 0;
}
为什么不会终止程序

#include<stdio.h>
int main(void)
{
    float length, width, c;
    printf("Enter the length of the rectangle: \n");
    while(scanf("%f",&length) )
    {
        printf("Length = %0.2f:\n", length);
        printf("Enter its width: \n");
        if(scanf("%.2f", &width) != 1.00)
            break;
        printf("width = %0.2f:\n", width);
        c = length * width;
        printf("Enter the length of 1 the rectangle:\n" );
    }
    printf("Done.\n");
    getchar();
    return 0;
}
注意你定义的是浮点型，if后输出的是浮点数而不是整数1.
还有，试试在if语句中把%f编成%.f(中间加个点)

注意那个if里scanf()函数的返回值！

scanf的返回值是成功读取数据的个数，成功读取了width就不会跳出

1.00后面改成1.000000   .2f改成f为什么不行  不是默认6位吗？

也许就是因为是默认的吧，给定位数的就没问题，还是确定位数吧，