C和指针第八章的两个简单代码

第五题其实也写了，但是不对所以不想贴了，矩阵运算实在使人头疼

//计算税收。以前觉得好像只能if实现，原来也可以这样#include <stdio.h>#include <stdlib.h>float stax( int money);static double income_limits[]={0, 23350, 56550, 117950, 256500};static float base_tax[]={0, 3502.5, 12798.5, 31832.5, 81710.5 };static float percent[]={ .15, .28, .31, .36, .396 };int main(){    int money;    float tax;    printf("输入收入!\n");    scanf("%d",&money);    tax = stax( money );    printf("税收是%f", tax);    return 0;}float stax( int money){    int category;    for(category = 0; (money >=income_limits[category]) && (category < 5);category+=1)        ;    category-=1;    return base_tax[category]+percent[category]*(money-income_limits[category]);}

#include <stdio.h>#include <stdlib.h>#include <string.h>//输入的每个单词与列表中的关键字比较，找到一个后返回这个匹配在列表中的偏移量，否则返回-1int lookup_keyword(char * desired, char *keywordtable[ ], int size);int main(){    int i;    char a[20];    printf("输入关键字!\n");    gets(a);    char *keyword[4] = {    "do",    "sr",    "tt",    NULL    };    i=lookup_keyword(a, keyword,3);    printf("匹配%d\n",i);    return 0;}int lookup_keyword(char * desired, char *keywordtable[ ], int size){    char **kwp;    //for(kwp = keywordtable; kwp < keywordtable + size; kwp++)//第一种    for(kwp = keywordtable; *kwp != NULL; kwp++)        if(strcmp( desired,*kwp ) == 0)        return kwp - keywordtable;    return -1;}