scanf、printf、putchar、getc、putc、fgets、fputs、sscanf、sprintf

fscanf和fprintf

fgets  从屏幕上获取输入(stdin)或者从文件中获取输入

fputs  输入到屏幕上(stdout)或者输出到文件中.

scanf   从屏幕上的输入格式化分离.

printf   输出到屏幕上.

sscanf  从字符串中格式化分离.

sprintf  输出到字符串中.

fscanf  从文件中格式化分离.

fprintf  输出到文件中.

fscanf

%d%c%d可能导致的bug

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

int count(int one, int tow, char symbol) {

switch (symbol) {

case '+':

return one + tow;

case '-':

return one - tow;

case '*':

return one * tow;

case '/':

if (!tow) {

return 0;

}

else { return one / tow; }

}

}

 

 

 

 

 

void main() {

FILE*read = fopen("1", "r");

if (!read) {

printf("文件为空");

system("pause");

return;

}

FILE*write = fopen("1", "w");

int kong = NULL;

int xiaomiao = NULL;

while (!feof(read)) {

int one; int tow; char symbol;

fscanf(read, "%d%c%d=\n", &one, &symbol, &tow);

int shaomiao = ftell(read);

if (shaomiao != kong) {

int result = count(one, tow, symbol);

fprintf(write, "%d%c%d=%d\n", one, symbol, tow, result);

 

}

}

fclose(read);

fclose(write);

system("pause");

}

#include<stdio.h>

#include<stdlib.h>

void main() {

FILE*read = fopen("1.txt", "r");

if (!read) {

printf("文件为空");

system("pause");

return;

}

int kong = NULL;

int xiaomiao = NULL;

while (!feof(read)) {

char name[20] = { NULL };

int age = NULL;

fscanf(read, "%[^,],%d\n",&name,&age );

int shaomiao = ftell(read);

if (shaomiao != kong) {

printf( "名字%s,年龄%d\n",name,age);

 

}

}

fclose(read);

system("pause");

}