1.
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#define FILE_NAME "name.txt"
int main(){
FILE *fp=fopen(FILE_NAME,"r");
if(NULL==fp){
printf("Failed to read the file %s \n",FILE_NAME);
exit(-1);
}
int ch=fgetc(fp);
int ch1;
printf("Name:");
while(ch!=EOF){
ch1 = ch;
if(ch1=='\n'){
printf("\nName:");
}
ch = fgetc(fp);
//printf("%d\n",ch1);
if(ch1==9&&isdigit(ch)) printf("\nAddress:");
if(ch1!='\n') putchar(ch1);
if(ch1=='.'&&ch==9){
printf("\nCity,State:");
}
}
fclose(fp);
return 0;
}
2.
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <ctype.h>
#define FILE_NAME "wage.txt"
int main(){
FILE *fp = fopen(FILE_NAME,"r");
if(fp == NULL){
printf("Can't open %s\n",FILE_NAME);
exit(EXIT_FAILURE);
}
printf("Name\t Social Security Number Total revernue\n");
int ch1,ch=fgetc(fp);
while(ch!=EOF){
ch1 = ch;
ch = fgetc(fp);
if(isdigit(ch1)&&ch=='.'){
int sum = 0;
while (ch!='\n'){
if(isdigit(ch)){
sum = sum*10 +(ch-48);
//printf("sum = %d\n",sum);
}
ch = fgetc(fp);
}
double para = ch1-48+(sum/100)/100.0;
printf("\t%.1lf",para*(sum%100));
}
putchar(ch1);
}
fclose(fp);
return 0;
}
3.
#include <stdio.h>
#include <stdlib.h>
#define FILE_NAME "text.dat"
int main(){
FILE *fp = fopen(FILE_NAME,"r");
if(fp == NULL){
printf("Can't open %s\n",FILE_NAME);
exit(EXIT_FAILURE);
}
char ch = fgetc(fp);
int cnt = 0;
while(ch!=EOF){
if(cnt%2==0) putchar(ch);
ch = fgetc(fp);
cnt++;
}
fclose(fp);
return 0;
}
//text.dat
hello, everyday! Today I will give a presentation about covid-19.
4.
//输入之前数据
30 60 40 80 90 120 150 130 160 170
#include <stdio.h>
#include <stdlib.h>
#define FILE_NAME "Pollen.dat"
int main(){
int num[10];
int number;
printf("enter a new number:");
scanf("%d",&number);
FILE *fp = fopen(FILE_NAME,"r");
if(fp == NULL){
printf("Can't open %s\n",FILE_NAME);
exit(EXIT_FAILURE);
}
int i = 0,total = 0;
while(!feof(fp)){
fscanf(fp,"%d",&num[i]);
//printf("%d\n",total);
total +=num[i];
i++;
}
//printf("%d\n",total);
fclose(fp);
for(i=0;i<9;i++){
num[i] = num[i+1];
}
num[9] = number;
for(i=0;i<10;i++){
printf("%d\n",num[i]);
}
fp = fopen(FILE_NAME,"w");
if(fp == NULL){
printf("Can't open %s\n",FILE_NAME);
exit(EXIT_FAILURE);
}
printf("The average for the past ten days is %d\n",total/10);
total = total -num[0]+num[9];
printf("The average for the last ten days is %d\n",total/10);
for(i=0;i<10;i++){
fprintf(fp,"%d ",num[i]);
}
fclose(fp);
return 0;
}
//输入190之后的数据
60 40 80 90 120 150 130 160 170 190
5.
#include<stdio.h>
#include<stdlib.h>
int main(int argc, char* argv[])
{
if(argc!=2){
printf("Usage: ./fs filename\n");
exit(-1);
}
FILE *rf=fopen(argv[1],"r");
if(NULL==rf){
printf("Failed to read the file %s \n",argv[1]);
exit(-1);
}
int ch;
int i=0;
long offset, last;
fseek(rf,0L,SEEK_END);
last=ftell(rf);
for(offset=0;offset<=last;offset++){
fseek(rf,-offset,SEEK_END);
ch=fgetc(rf);
switch(ch){
case '\n':break;
case EOF: break;
default:printf("%c",ch);break;
}
}
printf("\n");
fclose(rf);
return 0;
}
6.
3.
#include <stdio.h>
#include <stdlib.h>
int main(int argc,char *argv[]){
char str[100];
int num;
printf("the number of files is:");
scanf("%d",&num);
FILE *fp;
if(argc!=num+1){
printf("usage:canopen filename\n");
exit(EXIT_FAILURE);
}
for(int i=1;i<num+1;i++){
if((fp = fopen(argv[i],"r"))==NULL){
printf("%s can't be opened\n",argv[1]);
exit(EXIT_FAILURE);
}
int ch=fgetc(fp);
while(ch!=EOF){
putchar(ch);
ch = fgetc(fp);
}
fclose(fp);
}
return 0;
}
命令行下输入3个文件的名字，依次打开并打印之后关闭。
如果给出的文件数目与所要的文件数目不对应，程序会停止。
4.
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
int main(int argc,char *argv[]){
FILE *fp = fopen(argv[1],"r");
if(fp == NULL){
printf("Can't open %s\n",argv[1]);
exit(EXIT_FAILURE);
}
int cnt = 0,cnt_line=0,cnt_word=0;
char ch=fgetc(fp);
while(ch!=EOF){
if(isalpha(ch)){
cnt++;
}
if(ch=='\n'){
cnt_line++;
}
if(ch==' '){
cnt_word++;
}
putchar(ch);
ch = fgetc(fp);
}
fclose(fp);
printf("\n\nthe number of characters are %d\n",cnt);
printf("the number of lines are %d\n",cnt_line+1);
printf("the number of words are %d\n",cnt_word+1);
return 0;
}
7.
//txt文件 "telephone.txt"
404.817.6900
(215) 686-1776
312-746-6000
877 275 5273
6173434200
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#define FILE_NAME "telephone.txt"
int main(){
FILE *fp = fopen(FILE_NAME,"r");
if(fp == NULL){
printf("Can't open %s\n",FILE_NAME);
exit(EXIT_FAILURE);
}
int cnt_line = 0;
char ch=fgetc(fp);
while(ch!=EOF){
if(ch=='\n'){
cnt_line++;
}
//putchar(ch);
ch = fgetc(fp);
}
//fclose(fp);
//fp = fopen(FILE_NAME,"r");
rewind(fp);
for(int k=0;k<cnt_line+1;k++){
char str[100];
int i = 0,j = 0;
fgets(str,sizeof(str),fp);
printf("(");
while(i<10){
if(isdigit(str[j])){
printf("%c",str[j]);
i++;
if(i==3) printf(") ");
if(i==6) printf("-");
}
j++;
}
printf("\n");
}
//printf("%s",str);
fclose(fp);
return 0;
}
8.
#include<stdio.h>
#include<stdlib.h>
#include<ctype.h>
#define L 10
int main(int argc, char*argv[])
{
if(argc!=2)
{
printf("Usage: ./br filename\n");
exit(EXIT_FAILURE);
}
FILE *rf=fopen(argv[1],"rb");//rb是必需的
if(NULL==rf)
{
printf("Failed to open the file %s.\n",argv[1]);
exit(EXIT_FAILURE);
}
unsigned char buffer[L];//unsigned是必需的
int j=0;
printf("offset");
printf("\t");
printf(" Bytes ");
printf("\t");
printf("Characters\n");
printf("------");
printf("\t");
printf("-----------------------------");
printf("\t");
printf("----------\n");
while(1)
{
int n=fread(buffer,sizeof(unsigned char),L,rf);
//printf("n=%d\n",n);
if(n<=L)
{
printf("%6d\t",j);
j+=L;
int i;
for(i=0;i<n;i++)
{
printf("%02X",buffer[i]);
if(i<n-1)
printf(" ");
}
if(n<L)
{
for(i=n;i<L-1;i++)
printf(" ");
printf(" ");
}
printf("\t");
for(i=0;i<n;i++)
{
if(isprint(buffer[i]))
printf("%c",buffer[i]);
else
printf(".");
}
printf("\n");
if(n<L)
{
break;
}
}
}
fclose(rf);
return 0;
}
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