/*
    输入产品号，产品数量，计算总价
*/

#include<stdio.h>
#include <string.h>
int main( void )
{   
    // 初始化
    int i;
    int s;        //产品号
    int q;        // 产品数量
    double count[6] = {0};
    double total = 0;

    while( 1 ){
        printf( "please enter the number: \n" );
        scanf( "%d", &s );
        if( s == -1 )    break;
        scanf( "%d", &q );
        // 不同的产品好，计算不同的总价
        switch( s ){
            case 1 : count[1] += q * 2.98;
                break;
            case 2 : count[2] += q * 4.50;
                break;
            case 3 : count[3] += q * 9.98;
                break;
            case 4 : count[4] += q * 4.49;
                break;
            case 5 : count[5] += q * 6.87;
                break;
            case ' ':
            case '\t':
            case '\n':
                break;
            default: printf( "the number is wrong!!\n" );
                break;
        }// end switch
        
    }// end while

    //计算总价
        for( i = 1; i <= 6; i++ ){
            total += count[i];
        }// end for_i
        printf( "the totla money is %d!!!\n", total );
   
    return 0;
}// end main function
// 打个比方啊，本来我输入1,2，-1，按我的思路是输出5.96的，怎么老是输出2啊，

printf( "the totla money is %d!!!\n", total );
用%d去输出浮点型数据，这2天看见好多次了

还有个问题，那就是数组越界        for( i = 1; i <= 6; i++ )这里

#include<stdio.h>
#include <string.h>

int main( void )
{   
    // 初始化
    int i = 0;
    int s = 0;        //产品号
    int q = 0;        // 产品数量
    double count[6] = {0};
    double total = 0;

    while( 1 ){

        printf( "please enter a number: \n" );
        scanf( "%d", &s );
        if( s == -1 )   
            break;
        scanf( "%d", &q );
        
        switch( s ){
            case 1 :
                count[1] += q * 2.98;
                break;
            case 2 :
                count[2] += q * 4.50;
                break;
            case 3 :
                count[3] += q * 9.98;
                break;
            case 4 :
                count[4] += q * 4.49;
                break;
            case 5 :
                count[5] += q * 6.87;
                break;
            case ' ':
            case '\t':
            case '\n':
                break;
            default:
                printf( "the number is wrong!!\n" );
                break;
        }
        
    }

   
        for( i = 0; i < 6; i++ ){
            total += count[i];
        }
        printf( "the totla money is %.3f!!!\n", total );
   
    return 0;
}
---------------
没看懂你的程序什么意思
错误不少啊

看见了，谢谢你了

我是在做本书后的习题，所以注释比较少，可是我有很多细节错误，逻辑错误，还望多多关注，谢谢

还真是细节决定成败啊，哎，这错误。谢谢提醒了

//求大神看看，简单的问题，看看出在哪！！！
/*
输入产品号，产品数量，计算总价
*/

#include<stdio.h>
#include <string.h>
int main( void )
{
// 初始化
int i;
int s; //产品号
int q; // 产品数量
float count[6] = {0};
float total = 0;

while( 1 ){
printf( "please enter the number: \n" );
scanf( "%d", &s );
if( s == -1 ) break;
scanf( "%d", &q );
// 不同的产品好，计算不同的总价
switch( s ){
case 1 : count[1] += q * 2.98;
break;
case 2 : count[2] += q * 4.50;
break;
case 3 : count[3] += q * 9.98;
break;
case 4 : count[4] += q * 4.49;
break;
case 5 : count[5] += q * 6.87;
break;
case ' ':
case '\t':
case '\n':
break;
default: printf( "the number is wrong!!\n" );
break;
}// end switch

}// end while

//计算总价
for( i = 1; i <= 6; i++ ){
total += count[i];
}// end for_i
printf( "the totla money is %.2f !!!\n", total );

return 0;
}// end main function
// 打个比方啊，本来我输入1,2，-1，按我的思路是输出5.96的，怎么老是输出2啊，