1.比较两个字符串是否相等
#include <stdio.h>
int main(){
char str1[100];
char str2[100];
int i=0,j=0,len1=0,len2=0;
char str_stat,data_stat;
//1.录入两个字符串
printf("Please Input string: ");
scanf("%s%s",str1,str2);
//2.比较长度
while(str1[i++]!='\0'){
len1++;
}
while(str2[j++]!='\0'){
len2++;
}
if(len1==len2){
str_stat=1;
}
else{
str_stat=0;
}
//3.比较数据
data_stat=1;
i=0;
while(str1[i]!='\0'&&str2[i]!='\0'){
if(str1[i++]!=str2[i++]){
data_stat=0;
break;
}
}
//4.判断是否相等
if(str_stat==1&&data_stat==1){
printf("Yes\r\n");
}
else{
printf("No\r\n");
}
return 0;
}
2.从键盘上输入字符串 ,判断字符串中,小写字母、大写字母、数字、其他字符的个数.
#include <stdio.h>
int main()
{
char buff[100];
int data[4] = { 0 };
int i = 0;
printf("输入字符串:");
scanf("%s", buff); //遇到空格或者回车就结束
while (buff[i] != '\0')
{
if (buff[i] >= 'a' && buff[i] <= 'z'){
data[0]++; //小写字符
}
else if (buff[i] >= 'A' && buff[i] <= 'Z'){
data[1]++; //大写字符
}
else if (buff[i] >= '0' && buff[i] <= '9'){
data[2]++; //数字字符
}
else{
data[3]++; //其他字符
}
i++;
}
printf("小 写 :%d\n", data[0]);
printf("大 写 :%d\n", data[1]);
printf("数 字 :%d\n", data[2]);
printf("其他字符 :%d\n", data[3]);
return 0;
}
3.字符串转整数
#include <stdio.h>
int main(){
char str[100];
int i=0,value=0;
printf("Please Input data: ");//输入数字0~9
scanf("%s",str);
while(str[i]!='\0'){
value=value*10;
value+=str[i]-48;
i++;
}
printf("Value = %d\r\n",value);
return 0;
}
4. 整数转字符串
#include <stdio.h>
int main(){
int i=0,j=0,value;
char str[100];
printf("输 入 整 数 :");//输入0~2147483647之间
scanf("%d",&value);
while(value!=0){
str[i]=value%10+48;
value/=10;
i++;
}
printf("输出字符串 :");
for(j=i-1;j>=0;j--){
printf("%c",str[j]);
}
return 0;
}
5.查找单词
#include <stdio.h>
int main()
{
char src[100]={0}; //存放源字符串
char find[100]={0}; //查找的字符串
int src_len = 0;
int find_len = 0;
int i, j, cnt = 0;
//1. 录入字符串
printf("录入源字符串: ");
scanf("%s", src);
printf("录入查找的字符串:");
scanf("%s", find);
//2. 计算出字符串长度
while (src[src_len] != '\0')
{
src_len++;
}
while (find[find_len] != '\0')
{
find_len++;
}
//3. 查找字符串
for (i = 0; i<src_len; i++)
{
for (j = 0; j<find_len; j++)
{
if (src[i + j] != find[j]){
break;
}
}
if (j == find_len)
{
cnt++;
i = i + find_len - 1; //优化代码
}
}
//4. 结果
printf("[%s]的数量为[%d]个\n", find, cnt);
return 0;
}
6.字符串排序-(大->小)
#include <stdio.h>
int main()
{
char src[100]; //存放源字符串
int i = 0, j = 0;
int len = 0, tmp;
//1. 录入字符串
printf("请输入字符串:");
scanf("%s", src);
//2.得到字符串的长度
while (src[len] != '\0')
{
len++;
}
//3. 排序
for (i = 0; i<len - 1; i++) //总次数-轮
{
for (j = 0; j<len - 1 - i; j++)
{
if (src[j]<src[j + 1])
{
tmp = src[j];
src[j] = src[j + 1];
src[j + 1] = tmp;
}
}
}
//4. 结果
printf("%s\n", src);
return 0;
}
7.字符串拼接
#include <stdio.h>
#include <string.h>
char *my_strcat(char *str1, const char *str2);
int main(int argc, char *argv[])
{
char str[100] = "1234567890";
char *ptr = my_strcat(str, "abcdefg");
printf("str=%s\n", str);
printf("ptr=%s\n", ptr);
return 0;
}
/*
字符串拼接
*/
char *my_strcat(char *str1, const char *str2)
{
char *p = str1;
/*1. 将 p 指针移动到字符串结尾*/
while (*p != '\0'){ p++; }
/*2. 完成拼接*/
while ((*p++ = *str2++) != '\0');
return str1;
}
8.字符串拷贝
#include <stdio.h>
#include <string.h>
char *my_strcpy(char *str1, const char *str2);
char *my_strncpy(char *str1, const char *str2, int len);
int main(int argc, char *argv[])
{
char str[100] = "1234567890";
char str_copy[100]={0};
char *p_copy=my_strcpy(str_copy,str);
char *p = my_strncpy(str, "abcdefg", 4);
printf("COPY_1 : \r\n");
printf("\ts_copy = %s\n\tp_copy = %s\n",str_copy,p_copy);
printf("COPY_2 : \r\n");
printf("\tstr=%s\n", str);
printf("\tp=%s\n", p);
return 0;
}
//字符串拷贝
char *my_strcpy(char *str1, const char *str2)
{
char *p = str1;
while ((*str1++ = *str2++) != '\0');
return p;
}
//拷贝指定的个数
char *my_strncpy(char *str1, const char *str2, int len)
{
int i = 0;
char *p = str1;
while ((*str1++ = *str2++) != '\0')
{
i++;
if (i == len)break;
}
//*str1 = '\0';
return p;
}
9.简历学生管理系统
#include <stdio.h>
#include <string.h>
struct str
{
char name[50]; //姓名
int number; //学号
};
/********函数声明区域*********/
int MenuShow();
void AddInfo(struct str *p_info);
void FindInfo(struct str *p_info);
void print_info(struct str *p_info);
void del_info(struct str *p_info);
void add_info(struct str *p_info);
void sort_info(struct str *p_info);
/*******全局变量声明区域*******/
unsigned int InfoCnt = 0; //保存了信息的数量
struct str info[100]; //结构体数组
/********主函数***************/
int main(int argc, char*argv[])
{
int data;
while (1)
{
data = MenuShow();
switch (data)
{
case 1:
AddInfo(info); //添加学生信息
break;
case 2:
FindInfo(info); //查找学号
break;
case 3: //删除学生信息
del_info(info);
break;
case 4: //插入学生信息
add_info(info);
break;
case 5: //根据学号排序
sort_info(info);
break;
case 6:
print_info(info); //打印学生信息
break;
case 7:
printf("系统退出成功!\n\n");
return 0; //结束主函数
break;
}
}
return 0;
}
/*
菜单显示,获取用户的输入
*/
int MenuShow()
{
printf("*************欢迎使用 XXXX 学生管理系统****************\n");
printf("1. 录入学生信息\n");
printf("2. 查找学生信息\n");
printf("3. 删除学生信息\n");
printf("4. 插入学生信息\n");
printf("5. 根据学号排序\n");
printf("6. 打印所有学生信息\n");
printf("7. 退出\n");
printf("\n\n 请选择:");
int data; //C99
scanf("%d", &data);
return data;
}
/*录入学生信息*/
void AddInfo(struct str *p_info)
{
int i, num;
printf("请输入学生姓名: ");
scanf("%s", p_info[InfoCnt].name);
printf("请输入学号:");
scanf("%d", &num);
//查找学号是否冲突
for (i = 0; i<InfoCnt; i++)
{
if (p_info[i].number == num)
{
printf("学号冲突!\n");
return;
}
}
p_info[InfoCnt].number = num;
InfoCnt++;
}
/*查找学生信息*/
void FindInfo(struct str *p_info)
{
int i;
int num;
printf("请输入查找的学号: ");
scanf("%d", &num);
for (i = 0; i<InfoCnt; i++)
{
if (p_info[i].number == num)
{
printf("\n 查找成功!\n");
printf("姓名: %s,", p_info[i].name);
printf("学号: %d\n", p_info[i].number);
return;
}
}
printf("\n 输入的学号不存在!\n");
}
//打印所有的学生信息
void print_info(struct str *p_info)
{
int i;
for (i = 0; i<InfoCnt; i++)
{
printf("姓名: %s,", p_info[i].name);
printf("学号: %d\n", p_info[i].number);
}
}
//删除学生信息,以学号删除
void del_info(struct str *p_info)
{
if (InfoCnt == 0)
{
printf("系统中未录入信息!\n");
return;
}
int i, j;
int number; //输入的学号
printf("请输入学号:");
scanf("%d", &number);
for (i = 0; i<InfoCnt; i++)
{
if (p_info[i].number != number)continue;
for (j = i; j<InfoCnt; j++)
{
p_info[j] = p_info[j + 1];
}
}
InfoCnt = InfoCnt - 1;
}
//根据位置插入学生信息
void add_info(struct str *p_info)
{
int addr;//保存位置
int i;
printf("输入插入的位置:");
scanf("%d", &addr);
if (addr>InfoCnt || addr == 0)
{
addr = InfoCnt + 1;
}
addr = addr - 1;
for (i = InfoCnt - 1; i >= addr; i--)
{
p_info[i + 1] = p_info[i];
}
printf("输入姓名: ");
scanf("%s", p_info[addr].name);
printf("输入学号:");
scanf("%d", &p_info[addr].number);
InfoCnt++;
}
//排序
void sort_info(struct str *p_info)
{
int i, j;
struct str tmp;
for (i = 0; i<InfoCnt - 1; i++)
{
for (j = 0; j<InfoCnt - 1 - i; j++)
{
if (p_info[j].number > p_info[j + 1].number)
{
tmp = p_info[j + 1];
p_info[j + 1] = p_info[j];
p_info[j] = tmp;
}
}
}
}