Some simple c program

素颜马尾好姑娘i 2022-09-17 11:28 175阅读 0赞

/*****************************P1*****************************/
    #include <stdio.h>
    /**just a simple hello word**/
    int main(void)
    {
    	printf("hello, word");
    	return 0;
    }
    
    /*****************************P2*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    /**just a simple function**/
    int doubleNumber(int n){
    	return n+n;
    }
    
    /*****************************P3*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    int doubleNumber(int n);
    
    int main(int argc,char* args[]){
    	if(argc<2){
    		printf("Please input one arg.");
    		return -1;
    	}
    	int number = atoi(args[1]);
    	printf("%d double result is %d",number,doubleNumber(number));
    	return 0;
    }
    
    /*****************************P3*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    /**Read File Content**/
    int main(int argc,char* args[]){
    	if(argc<2){
    		printf("Please input the file name.\n");
    		return -1;
    	}
    	char* fileName=args[1];
    	FILE *fp;
    	char* line;
    	
    	if(access(*fileName,0)){
    		printf("The file %s cannot be access.",fileName);
    	}
    	
    	if((fp=fopen(fileName,"r"))==NULL){
    		printf("The file %s is not exists or can not be read.",fileName);
    		return -1;
    	}
    	
    	while (!feof(fp)){
    		if(fgets(line,9999,fp)!=NULL){
    			printf("Read content:%s",line);
    		}
    	}            
        fclose(fp);
    	return 0;
    }
    
    /*****************************P4*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    /**Call Linux command**/
    int main(int argc,char* args[]){
    	int result;
    	result=system("ls -l");
    	printf("the result call linux command is %d",result);
    	return 0;
    }
    
    /*****************************P5*****************************/
    #include <sys/types.h>
    #include <unistd.h>
    #include <stdlib.h>
    #include <stdio.h>
    #include <string.h>
    /**Call Linux command by popen and get the result**/
    int main(int argc,char* args[]){
    	int result;
    	FILE *stream;
    	char buf[1024];
    	memset(buf,'\n',sizeof(buf));
    	stream=popen("ls -l","r");	
    	fread(buf,sizeof(char),sizeof(buf),stream);
    	printf("the result is:\n %s",buf);
    	pclose(stream);
    	return 0;
    }
    
    /*****************************P6*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    /**Show time**/
    int main(int argc,char* args[]){
    	while(1==1){
    		system("date");
    		sleep(1);
    	}
    	return 0;
    }
    
    /*****************************P7*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    /**Show time in a new line, just append effect**/
    int main(int argc,char* args[]){
    	while(1==1){
    		system("date");
    		printf("\033[1A"); //back to last line
            printf("\033[K");  //clean this line
    		sleep(1);
    	}
    	return 0;
    }
    
    /*****************************P8*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    /**Show time, but remove before time, just keep current time**/
    int main(int argc,char* args[]){
    	FILE *stream;
    	char buf[1024];
    	memset(buf,'\0',sizeof(buf));
    	while(1==1){
    		stream=popen("date","r");
    		fread(buf,sizeof(char),sizeof(buf),stream);
    		pclose(stream);
    		printf("%s",buf);
    		printf("\033[1A"); //back to last line
            printf("\033[K");  //clean this line
    		sleep(1);
    	}
    	return 0;
    }
    
    /*****************************P9*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    /**Show time, but remove before time, just keep current time**/
    int main(int argc,char* args[]){
    	FILE *stream;
    	char buf[1024];
    	memset(buf,'\0',sizeof(buf));
    	system("clear");
    	while(1==1){
    		stream=popen("date","r");
    		fread(buf,sizeof(char),sizeof(buf),stream);
    		pclose(stream);
    		printf("\033[1A"); //back to last line
            printf("\033[K");  //clean this line
    		printf("%s",buf);
    		sleep(1);
    	}
    	return 0;
    }
    
    /*****************************P10*****************************/
    #include <stdio.h>
    #include <stdlib.h>
    #include <unistd.h>
    /**Show multi dynamic lines in the screen, like the top command**/
    int main(int argc,char* args[]){
    	FILE *stream;
    	char buf[1024];
    	int currentLine;
    	memset(buf,'\0',sizeof(buf));
    	//clear the screen
    	system("clear");
    	while(1==1){
    		//get current date
    		stream=popen("date","r");
    		fread(buf,sizeof(char),sizeof(buf),stream);
    		pclose(stream);
    		
    		printf("\033[2A"); //back to last 2 line, see the usage:http://blog.csdn.net/xiaowall/article/details/8299985
    		currentLine=1;
    		while(currentLine<2){  //loop remove the line in the screen
            	printf("\033[K");  //clean current line
            	currentLine++;
            }
    		printf("%s",buf);
    		printf("%s",buf);
    		sleep(1);
    	}
    	return 0;
    }