作业练习

1    使用while循环实现九九乘法表

#includeint main(int argc, char **argv)

{

int i=1;

int j=1;

while(i<10)

{

j=1;

while(j<=i)

{

printf("%d*%d=%d",i,j,i*j);

j++;

}

printf("\n");

i++;

}

return 0;

}

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2  .for或者while实现打印等腰三角形，行数由用户输入

#include

main()

{

int i,j,k,n,t;

printf("请输入行数\n");

scanf("%d",&n);

for(i=1;i<=n;i++)

{

for(j=1;j<=n-i;j++)

{

printf(" ");

}

for(k=1;k

{

printf("*");

}

for(t=1;t

printf("*");

printf("\n");

}

}

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3  写一个脚本，判断给定目录下的文件属性

#!/bin/bash

read -p "please input the file name:" file

if [ ! -n "$file" ];

then

echo please input the file name please

exit 0

fi

ls $file > /dev/null 2>&1

if [ $? -eq 0 ]

then

echo file exist

cp $file $file.bak

vi $file

else

echo file not exist!

fi