55
实验1.1:
#include <stdio.h> #define N 4 int main() { int x[N] = {1,9,8,4}; int i; int *p; for(i=0;i<N;++i) printf("%d",x[i]); printf("\n"); return 0; }
#include <stdio.h> #define N 4 int main() { int x[N] = {1,9,8,4}; int i; int *p; for(p=x;p<x+N;++p) printf("%d",*p); printf("\n"); return 0; }
#include <stdio.h> #define N 4 int main() { int x[N] = {1,9,8,4}; int i; int *p; p=x; for(i=0;i<N;++i) printf("%d",p[i]); printf("\n"); return 0; }
#include <stdio.h> #define N 4 int main() { int x[N] = {1,9,8,4}; int i; int *p; p=x; for(i=0;i<N;++i) printf("%d",*(p+i)); printf("\n"); return 0; }
实验1.2
#include <stdio.h> int main() { int x[2][4] = {{1,9,8,4},{2,0,4,9}}; int i,j; int *p; int (*q)[4]; for (i=0;i<2;++i) { for(j=0;j<4;++j) printf("%d",x[i][j]); printf("\n"); } for(p=&x[0][0],i=0;p<&x[0][0]+8;++p,++i) { printf("%d",*p); if((i+1)%4==0) printf("\n"); } for (q=x;q<x+2;++q) { for(j=0;j<4;++j) printf("%d",*(*q+j)); printf("\n"); } return 0; }
实验2.1:
#include <stdio.h> #include <string.h> #define N 80 int main() { char s1[] = "Learning makes me happy"; char s2[] = "Learning makes me sleepy"; char tmp[N]; printf("sizeof(s1) vs. strlen(s1): \n"); printf("sizeof(s1) = %d\n", sizeof(s1)); printf("strlen(s1) = %d\n", strlen(s1)); printf("\nbefore swap: \n"); printf("s1: %s\n", s1); printf("s2: %s\n", s2); printf("\nswapping...\n"); strcpy(tmp, s1); strcpy(s1, s2); strcpy(s2, tmp); printf("\nafter swap: \n"); printf("s1: %s\n", s1); printf("s2: %s\n", s2); return 0; }
运行:
问题一:s1的大小是24;sizeof(s1)计算的是S1的大小:strlen(s1)计算的是S1的实际长度;
问题二:不能。s1表示的是变量;s1[]表示的是字符串;
问题三:交换了;
实验2.2:
#include <stdio.h> #include <string.h> #define N 80 int main() { char *s1 = "Learning makes me happy"; char *s2 = "Learning makes me sleepy"; char *tmp; printf("sizeof(s1) vs. strlen(s1): \n"); printf("sizeof(s1) = %d\n", sizeof(s1)); printf("strlen(s1) = %d\n", strlen(s1)); printf("\nbefore swap: \n"); printf("s1: %s\n", s1); printf("s2: %s\n", s2); printf("\nswapping...\n"); tmp = s1; s1 = s2; s2 = tmp; printf("\nafter swap: \n"); printf("s1: %s\n", s1); printf("s2: %s\n", s2); return 0; }
运行:
问题一:s1中存放的是字符串;sizeof(s1)计算的是S1的大小:strlen(s1)计算的是S1的实际长度;
问题二:不能,s1是指针变量的名称不能存放内容;
问题三:交换的是两个变量里存储的内容;在内存存储单元中没有交换;
实验三:
#include <stdio.h> void str_cpy(char *target, const char *source); void str_cat(char *str1, char *srt2); int main() { char s1[80], s2[20] = "1984"; str_cpy(s1,s2); puts(s1); str_cat(s1, " Animal Farm"); puts(s1); return 0; } void str_cpy(char *target, const char *source) { while (*target++=*source++); } void str_cat(char *str1, char *str2) { while (*str1) str1++; while (*str1++ = *str2++); }
运行:
实验四:
#include <stdio.h> #define N 80 int func(char *); int main() { char str[80]; while (gets(str) !=NULL) { if (func(str)) printf("yes\n"); else printf("no\n"); } return 0; } int func(char *str) { char *begin, *end; begin = end = str; while (*end) end++; end--; while(begin<end) { if(*begin !=*end) return 0; else { begin++; end--; } } return 1; }
运行:
实验五:
//task5
#include <stdio.h>
#define N 80
void func(char *);
int main()
{
char s[N];
while (scanf("%s", s) != EOF)
{
func(s);
puts(s);
}
return 0;
}
void func(char *str)
{
int i;
char *p1, *p2, *p;
p1 = str;
while (*p1 == '*')
p1++;
p2 = str;
while (*p2)
p2++;
p2--;
while (*p2 == '*')
p2--;
//line26-36保留了字符串两端的‘*’
p = str;
i = 0;
while (p < p1)
{
str[i] = *p;
p++;
i++;
}
while (p <= p2)
{
if (*p != '*')
{
str[i] = *p;
i++;
}
p++;
}
while (*p != '\0')
{
str[i] = *p;
p++;
i++;
}
//保留了开头与结尾的‘*’,并剔除了字母中间的‘*’
str[i] = '\0';
}
运行:
实验六:
//task6_1 #include <stdio.h> #include <string.h> void sort(char *name[], int n); int main() { char *course[4] = {"C Program", "C++ Object Oriented Program", "Operating System", "Data Structure and Algorithms"}; int i; sort(course, 4); for (i = 0; i < 4; i++) printf("%s\n", course[i]); return 0; } void sort(char *name[], int n) { int i, j; char *tmp; for (i = 0; i < n - 1; ++i) for (j = 0; j < n - 1 - i; ++j) if (strcmp(name[j], name[j + 1]) > 0) //比ascii码 ,进行排序 { tmp = name[j]; name[j] = name[j + 1]; name[j + 1] = tmp; } }
//task6_2 #include <stdio.h> #include <string.h> void sort(char *name[], int n); int main() { char *course[4] = {"C Program", "C++ Object Oriented Program", "Operating System", "Data Structure and Algorithms"}; int i; sort(course, 4); for (i = 0; i < 4; i++) printf("%s\n", course[i]); return 0; } void sort(char *name[], int n) { int i, j, k; char *tmp; for (i = 0; i < n - 1; i++) { k = i; for (j = i + 1; j < n; j++) //每一次选一个最小的,对应的次序存在k里 if (strcmp(name[j], name[k]) < 0) k = j; if (k != i) { tmp = name[i]; //指针数组内存着指针,此处只发生指针的交换 name[i] = name[k]; name[k] = tmp; } } }
运行:
实验七:
#include <stdio.h> #include <string.h> #define N 5 int check_id(char *str); // 函数声明 int main() { char *pid[N] = {"31010120000721656X", "330106199609203301", "53010220051126571", "510104199211197977", "53010220051126133Y"}; int i; for (i = 0; i < N; ++i) if (check_id(pid[i])) // 函数调用 printf("%s\tTrue\n", pid[i]); else printf("%s\tFalse\n", pid[i]); return 0; } // 函数定义 // 功能: 检查指针str指向的身份证号码串形式上是否合法。 // 形式合法,返回1,否则,返回0 int check_id(char *str) { if(strlen(str) != 18) return 0; if((str[17] >= 48 && str[17] <= 57) || str[17] == 'X') return 1; return 0; }
运行:
实验八:
#include <stdio.h> #define N 80 void encoder(char *s); // 函数声明 void decoder(char *s); // 函数声明 int main() { char words[N]; printf("输入英文文本: "); gets(words); printf("编码后的英文文本: "); encoder(words); // 函数调用 printf("%s\n", words); printf("对编码后的英文文本解码: "); decoder(words); // 函数调用 printf("%s\n", words); return 0; } /*函数定义 功能:对s指向的字符串进行编码处理 编码规则: 对于a~z或A~Z之间的字母字符,用其后的字符替换; 其中,z用a替换,Z用A替换 其它非字母字符,保持不变 */ void encoder(char *s) { do { if((*s >= 'a' && *s <= 'y') || (*s >= 'A' && *s <= 'Y')) { *s += 1; continue; } if(*s == 'z') *s = 'a'; if(*s == 'Z') *s = 'A'; }while(*(s++)); } /*函数定义 功能:对s指向的字符串进行解码处理 解码规则: 对于a~z或A~Z之间的字母字符,用其前面的字符替换; 其中,a用z替换,A用Z替换 其它非字母字符,保持不变 */ void decoder(char *s) { do { if((*s >= 'b' && *s <= 'z') || (*s >= 'B' && *s <= 'Z')) { *s -= 1; continue; } if(*s == 'a') *s = 'z'; if(*s == 'A') *s = 'Z'; }while(*(s++)); }